HIPLEX 1976 Operations Plan: Miles City, Montana

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'HIPLEX
1976 OPERATIONS PLAN
MILES CITY, MONTANA
Site headquarters located
at Miles City Airport
1 mile north of Miles City
on Highway 11 (North 7th St)
Mailing Address
High Plains Cooperative Program (HIPLEX)
P.O. Box 1350
Miles Cily, MT 59301
Phone Number
(406) 131-5030
DEPARTMENT OF THE INTERIOR
Bureau of Reclamation
J
1. HIPLEX OVerview and Objectives............... 1-1
A. Introduction.......................... I-I
B. HIPLEX History........................ 1-2
C. Specific Objectives for 1976 1-6
D. Nonlleteorological Impact
Investigations ...............••••.•• 1-11
II. Observation Systems ..•.•.•.•.•...•....•...•.• II-I
A. Aircraft Observations ...•.••••••.•..•. II-I
CSI Cloud-top Aircraft .....•....••..... 11-4
MRI Cloudbase Aircraft •..•.••••.••...•. 11-8
Aerosol Aircraft ........•••....••..•••. 11-9
Survey and Seeding Aircraft............ 11-9
Aircraft Camera Systems ....•...••..•.•• 11-10
B. Radar Observations II-Il
CONTENTS - continued
C. Surface Precipitation Networks ....••.. II-IS
Primary Rain Gage Network ....•••...•... II-17
Rain Gage Clusters II-18
LANDSAT Rain Gage System............... II-19
Memory Rain Gage System................ II-20
D. Rawinsonde Observations .......•.••.••• II-21
E. Ground-based Cloud Condensation
and Ice Nucleus Measurements •.....•. II-22
F. Ground-based Phot9sraphy ..........•.•• I1-23
G. Satellite Data........................ 11-25
H. Weather Data Systems for
Forecasting......................... 11-26
III. Operational Considerations and Procedures .... III-l
A. Daily Field Opera-dons................ III-l
General Scheduling..................... IIT-l
Daily Schedule of Operations •..•.•.••.. ITT-3
ii
CONTENTS - continued
Debriefing Sessions .........•••••...••.
Daily Briefing Sessions- ••..........•. ; ..
Forecasts ...••............•........••..
Baker, Montana, Downwind Site ......•...
Airspace Coordination ........•.••..•...
Suspension Criteria •......•.......•....
B. Aircraft Utilization •.. ; •.•.•........•
CSI Cloud Physics Aircraft ••..........•
MR.I Cloud Physics Aircraft ..•....•.....
Aerosol Aircraft .................•..•..
Survey and Seeding Aircraft •.....•...•.
Decisions ........•...............•.•.•.
Calibration .......••..••...••.•.••.....
C. Radar Utilization· .....•...•....•....•.
Miles City Radar .
Baker Radar ...........•........•.......
iii
111-3
111-6
1II-7
III-8
III-9.
III-lO
111-14
III-24
III-25
III-27
111-29
III-31
III-33
III-36
III-36
III-45
CONTENTS - continued
D. Rawinsonde Observations ...•.•.•.......
E. Surface Measurements •...•..•......•...
Precipitation .......•.....•.••.........
Cloud Condensation and Ice Nuclei .
Photography ...........••..•.•.•.......•
111-49
III-52
III-52
III-59
III-61
F. Satellite Data Collection and
Analysis ......•••...•.••••..•...•..• 111-62
Digital Data Collection from
Nhite Sands Missile Range (KSMR)
G. Safety Considerations ....•...•....•...
Aircraft Operations .
Persons Allowed on HIPLEX Flights .....•
Radar Operations .
General Field Operations •......•.......
Fire ..•••.•........•...•............•..
iv
111-64
111-65
111-65
111-66
111-68
111-68
111-72
c
CONTENTS - continued
IV. Data Management............................... IV-l
A. Aircraft •.. ~.......................... IV-l
B. Radar................................. IV-2
C. Precipitation Networks................ IV-6
Belfort Rain Gage Data................. IV-6
LANDSAT Rain Gage Data................. IVw7
Memory Rain Gage Data.................. IV-8
Wedge-type Rain Gage Data.............. IV-8
Hail Pad Data •... ,...................... IV-9
D. Rawinsonde............................ IV-9
E. Cloud Condensation and
Ice Nuclei •.•••.•••••..••••..••••••• IV-II
F. Surface Photography................... IV-II
G. Satellite Data........................ IV-12
V. Support Facilities •••....•....•..•.•....•.•.. V-I
CONTENI'S • continued
A. Transportation........................ V~l
Federal Motor"Vehicles •..•...•••..•.•.. V-I
State Motor Vehicles V-I
Private Contractors.................... Y·2
COIMlercial Transportation Services •.... V-2
B. COIIJIlUnications and Cosputer
Time-share Systea •.••....•••.••..••• V-3
Telephone Communications ••..•..•••••••• Y-3
Radio CollllllUtlications •......•....•.••••. V-4
Computer Time-share System............. V~4
c. Shop Facilities •..••..••.•.•...••...•• V-5
APPENDIX~S
Appendix A SlfR-75 Radar Operating Capabilities A-l
Appendix B Radar Operato.r 1s Checklists ......•..•.•...• 8·1
vi
APPENDIXES - continued
Appendix C FOnlat for Radar Magnetic Tape Labels C-l
Appendix D Electronic and Sphere Calibration
Procedures: Miles City and
Baker Radars '............................. D-l
Appendix E Aircraft Calibration Experimentation
at Miles City ......•.............•...••.. E-1
, j
Appendix F Miles City HIPLEX Field Operations
Participants and Organizations •.....•...• F-l
Appendix G Sunset and Evening ~ivil Twilight
Times for Miles City. torr (~IDT) •....••...• G-l
Appendix H Local Advisory Committee................... H-1
Appendix J Satellite Sector Descriptions and
Data Logs ..•..•••..••••••••••••.•.•..••..•. J-1
vii
TABLES
1. Measured parameters of
HIPLEX aircraft systems
2. Skywater C-band radar (SWR-75)
general systca specifications
3. Daily operations schedule .•.•••••.••.•••••....
4. Data outputs expected on pap.er by 1030
on the day following cach flight ••.•.•••••..
1I-3
11-13
I1I-4
5. Rainfall rate vcrs.us dBz
for SWR-75 at a 42-km range................. A-21
6. Satellite observation log' code................ J-8
viii
FIGURES
1. Map of Miles City experimental area
and facilities.............................. 1-3
2. Standard flight patterns for
cloud penetrations.......................... 111-21
3. Aircraft positions during
missions for CSI. MRI. aerosol (A).
and survey/seeder (ss) aircraft .......•••••• 111-23
4.
s.
6.
7.
SWR-75 operators notebook ......•.•...•...•....
Magnetic tape data format ........••..•...•....
VSWR versus power values ....•........••..•....
HIPLEX organization chart , .....•.•...•...•••••
111-46
A-22
0-32
F-6
8. Satellite observation sectors
(4 sheets) .••.•.•••.•••........•...•........ J-3
ix
FIGURES - continued
9. HIPLEX satellite obs.~at1on 10; •...•••••••••• J·7
10. LASERPAX data 101 ••••••••••••••••••••••••••••• J·12
HIPLEX 1976 OPERATIONS PLAN
FOR
MILES CITY, OONTANA
1. HIPLEX Overview and Objectives
A. Introduction
The lIigh Plains Cooperative Program DUPLEX) is part of the Bureau
of Reclamation's Project Skywater. Project Skywater has the overall
goal of developing an effective weather modification technology, sci­entifically
and socially acceptable. for precipitation management to
serve a portion of the Nation's \~ater resources needs.
The overall objective of IIlPLEX i~ to develop this technology for the
High Plains. The il:nnediate objective is to attain operational capa­bility
with showery. wal'1ll-season cumulus precipitation, with the pros­pect
that investigation of precipitation from cyclonic and upslope
cloud systems will follow.
Three experimental areas have been chosen for HIPLEX. These surround
Mi les City. Mont., Colby-Goodland, Kan., and Big Spring-Snyder, Tex .•
representing, respectively, the northern. central, and southern High
Plains. Three sites were chosen because climatic conditions and cloud
I-I
characteristics vary significantly over the north-south extent of the
High Plains. It is Wllikely that each portion of the overall HIPLEX
field research will receive equal ecphasis at each site. Certain
activities can be concentrated at a single she with good assurance
that the understanding gained will be reasonably applicable to the
entire High Plains (for example. field calibradon of seeding sys-tems).
Other types of activites. such as examination of cloud micro-physical
processes, may require work at each site because of known or
suspected north-south gradients in cloud and climatic properties.
This document concerns field operations to be conducted in the Mi les
City area during the 1976 SUllU1ler field season. which will extend from
April 22 through July 31. Figure 1 shows the general project area
and location of facilities.
B. HIPLEX History
After the Bureau of Reclamation was assigned as lead agency for IHPLEX.
a preliminary scientific plan. the HIPLEX Technical Plan. was prepared
by the Bureau's Division of Atmospheric Wat.er Resources·Management
(DAWRlot). The plan was distributed to many scientists and interested
individuals and organizations du;ing early 1974. A workshop (held at
Vail. Colo., July 22-25, 1974) used the preliminary Technical Plan as
a useful "stepping stone" in pursuing the development of an opdrnum
1-2
fi.ap of Miles City. Montana
E:qler1Jnental Area and Facilities
Figure 1. - Map of Miles City experimental area and facilities.
1-3
:.j'.
o
scientific approach for BIPLEX. The many valuable discussions held
at this workshop, together with the considerable correspondence that
followed, have been fully considered by DAl'iRM.
Another noteworthy workshop was held at Colorado State University,
October 10-12, 1974. The primary topic of this workshop was the
design of the Colby-Goodland, Kan., portion of IlIPLEX. However, most
of the discussion was general in nature and applicable to all HIPLEX
sites.
The first BIPLEX field activity took place at Miles City during mid­July
to mid-August, 1974. A limited program of radar and' ground-based
photographic observations was carried out. Data obtained were useful
in planning the Montana field activities for the 1975 season.
Field operations were conducted at the three HIPLEX sites during the
1975 sununer. In large measure, this field season was devoted to the
installation, testing, and general "shakedown" of a wide .variety of
experimental equipment and procedures. In addition, complete field
facilities had to be established in Kansas and Montana before and
during the field season. As equ,ip1l}ent was brought "online," data
collection commenced. A considerable 'amount of precipitation, rawin­sonde,
and radar data were 'acquired at- each site. -In addition, survey
flights were .successfully completed at all sites; these established
1-4
the detailed characteristics of the background aerosol. Also, at
least a limited amount of sampling of cloud microphysical and dynamic
processes was carried out at each experimental site.
The first of a series of HIPLEX Technical Conferences involving the
entire HIPLEX "family," representing all contractor £inns and agen­cies,
and DA1'm,M staff, was held in Denver on June 16-20, 1975. During
that conference, special panels met to make recommendations concerning
five aspects of HIPLEX bearing on analysis: (1) precipitation meas­urement,
(2) synoptic/mesoscale studies, (3) cloud/subcloud studies,
(4) intensive case studies, and (5) value analysis. Participants rec­ommended
additional HIPLEX technical conferences before and after each
operating season. The second such workshop was also held in Denver
on December 16-18, 1975. At this time several written reports were
presented describing the preliminary results of the 1975 field sea­son's
activity. Additional workshops are planned at several month
intervals. These conferences are proving invaluable for program
planning and coordination.
Discussions developed at the workshops, concerning HIPLEX design,
have continued at DAWRM, reSUlting in many of the ideas being incor­porated
into the plans. The experimental design for HIPLEX, being
cooperatively developed by the staffs of DAWRM and the Illinois State
l'later Survey, is of an evolving nature. As knowledge increases, it
1-5
will be used to modify and upgrade the experiment to optimize the
learning efficiency of HIPLEX. The present concept is that HlPLEX
will be a three-phase experiment. The first phase is of an explor­atory
nature leading to a better tmderstanding of natural precip­itation
processes and the design of a quasi-isolated cloud seeding
experiment. The activites of the 1976 season will be part of the
first phase. The second phase will be the actual conduct of the quasi­isolated
cloud seeding experiment which, if successful, will lead to
the design of a wide-area cloud seeding experiment. The third and
final phase would be a wide-area experiment attempting to increase
the net rainfall over several thousand square kilor.leters.
C. Specific Objectives for 1976
It has been decided that an improved physical understanding of natural
cloud and precipitation mechanisms in the northern High Plains should
precede a final design for testing seeding hypotheses. The existing
evidence is not sufficiently clear. on several critical points. More­over,
certain experimental procedures concerning the actual seeding of
clouds and the measurement of precipitation require explanation. Among
the more important questions that should be answered more fully are:
(1) What -is the role of naturally fonned ice crystals in the area's
rainfall regimes? At what· temperature levels· and in what.l.concen­trations
,do they:: occur? \'Ihat is the role of riming?
1-6
(2) What is the natural cloud droplet concentration and size
spectra as a function of cloud life cycle for important cloud
regimes? Is the coalescence mechanism important and does hygro­scopic
seeding appear to have potential?
(3) What is the climatology of clouds by type, size, and fre­quency?
\'ihat is the associated atmospheric structure as revealed
by rawinsondes? How are rainfall amount, frequency, and mechanism
related to cloud types?
(4) What delivery methodes) for cloud seeding agents are most
effective for various storm types? How rapidly do the seeding
agents diffuse through the cloud systems? What concentrations of
ice crystals actually resul t in the cloud from introduction of a
given type and amount of ice nuclei?
(5) What is the most practical and reliable method of measuring
rainfall (a) from quasi-isolated convective clouds, and (b) over
an area of several thousand square kilometers? Does seeding lead
to significant changes in the drop-size distribution and, hence,
the Z-R relationship? How important is evaporation below the radar
beam? \'ihat rain-gage density is sufficient for evaluation of a
quasi-isolated cloud seeding experiment? Is a combination of radar
and gages the best approach and, if so, what is the optimum combi­nation
configuration?
1-7
The operations plan for the 1976 field season is intended to expand
the preliminary efforts of the 1975 season in further solving these
and other similar important questions for the Miles City region. It
would be optimistic to believe that these questions could be answered
fully during the 1976 field season. However, it is believed that a
substantially improved state of knowledge will reSUlt, which will
guide further research efforts.
In order to improve understanding of natural cloud processes and cer­tain
aspects of weather modification technOlOgy, several specific
objectives have been established for the 1976 field season in Hontana.
These objectives, along with some specific approaches to meeting the
objectives, are listed below.
(1) Obtain the necessary data to evaluate whether radar alone,
rain gages alone, or some combination of the two systems provides
the most practical and reliable oethod of obtaining rainfall meas­urements
for evaluation of cloud seeding. This will be partially
accomplished by operating a primary network of 109 rain gages (plus
6 cluster networks of 3 gages each) in combination with two 5-cm
digitized radars monitoring the convective storms from opposite
sides. Additional measurements· pertinent to this problem will
include airborne and ground disdrometer measurements of the vari­ation
of Z-R relationships with time and space. Airborne dis­drometer
data will also be obtained above the rain gages while
1-8
within the radar beam. AUempts will be made to estimate evap­oration
between cloudbase and the ground. The two radars will
monitor convective stOI'lllS from opposite sides to help estimate
attenuation. The need for providing windshields for rain gages
will be evaluated from field data. Hail pads at all gage sites
will help clarify the potential problem of marked changes in the
Z-R relationship due to the presence of hail.
(2) Obtain detailed data from cloud physics aircraft. radar, rawin­sonde,
and possibly rain gages which will permit in-depth case
study analysis of several convective cloud systeJ:ls. Such infor­mation
is vital to an improved tmderstanding of convective cloud
precipitation processes. Numerical model testing and development
will be utilized extensively in this regard.
(3) Collect information concerning the mean frequency distributions
of several important cloud properties which bear on the potential
for weather modification. Examples include ice-nuclei and ice­crystal
concentrations as a function of temperature and time, cloud
condensation nuclei as a function of supersaturation, cloud droplet
spectra, sizes and magnitudes of cloud updrafts, cloud diameters,
heights and temperatures of both c10udbase and top as a function
of the cloud life cycle, and first echo heights and temperatures.
Survey flights will be routinely made by a light aircraft with
1-9
limited instrumentation to docwnent some of these properties.
Others will be determined by radar. by ground- and aircraft-based
time-lapse cameras, or by cloud physics aircraft during intensive
sampling of convective clouds. Rawinsonde data will be combined
with data from the other measurement systems to estimate certain
properties (for example. cloud-top temperatures).
(4) Investigate the dispersion of seeding material within clouds
for three modes of seeding (cloudbase, at the minus S° C level,
and from cloud top). Also, attempt to document ice crystal devel­opment
caused by seeding. This general area of research is referred
to as "calibration seeding" and is intended to test the three seed­ing
modes under actual field conditions. The question to be exam-ined
is: To what extent does silver iodide seeding of a particular
mode, with a known type and amount of material, modify the ice crys­tal
development and growth within small- to moderate-size convective
clouds? Al though cloud seeding has be~n conducted for the last
three decades, documentation of seeding-induced microphysical changes
within clouds is still quite limited. The calibration seeding
to be conducted during 1976 will build on the recent work by NCAR.
Instruments aboard a sailplane were used to detect both the seeding
material (as ice nuclei) and ice crystal concentrations. In the
planned HIPLEX work, powered aircraft will repeatedly.penetrate
a seeded cloud to 'monitor ice nuclei and ice crystal ·concentrations.
1-10
(5) Develop objective forecasting techniques for the formation of
convective clouds, and an estimate of their natural precipitation
potential including probable area and mean amount. Forecasting
will, of course, be quite useful in planning each day's activity.
Even more important, objective forecasting could be very helpful
in the design and conduct of future weather modification exper­imentation
us it may provide a basis for prepartitioning of the
data. This could lead to much more sensitive statistical testing
of seeding effectiveness.
D. Nonmeteorological Impact Investigations
I'/hile this operations plan covers only the meteorological portion of
Miles City llIPLEX, other important aspects should also be noted. The
Montana Department of Natural Resources and Conservation is directing
a research program concerned with the agricultural, economic, environ­mental,
hydrologic, and social aspects of potential swnmer rainfall
modification. Thus, if llIPLEX succeeds in demonstrating area-wide
rainfall changes, the significant consequences of such changes should
also be tmderstood.
1-11
'- .. ' .' ~
"' , ~';:r. _-....- .
. .•• ~J ";'" •
. .' ... t ~~_l' :., ... ;.:..:
II. Observation System
A. Aircraft Observations
One of the primary goals of 1976 will be to develop an improved
understanding of the natural precipitation mechanisms in the Miles
City area. This should indicate some of the potential for cloud
IllOdification for the purpose of increasing rainfall at the ground.
Remote observations by radar. rain gages, and photography cannot
give details of the microphysical processes that fortll the rain.
Rather, direct, in-cloud observations as obtained by instrumented
ai rcraft. are needed.
Another primary goal for 1976 is to establish the spatial and tem­poral
variability of Z-R relationships for precipitating clouds in
the Miles City area. This will aid in evaluation of radar as a rain­fall
measuring tool for future seeding experiments. The aircraft are
needed to measure rainfall rates in volumes eXaJIlined by the radar and
to document the precipitation mechanism that is involved on an indi­vidual
case basis.
Three instrumented cloud physics aircraft will be utilized during
1976. The cloud physics aircraft intended for use primarily above
cloudbase is an Aero COmJll8J\der 680 FL operated by Convergence Sys­tems,
Inc. (CSt) of Ft. Collins, Colo. A second cloud physics air­craft.
nomally flOto'Jl. near cloudbase. will be a Piper Navajo, operated
II-I
by Meteorology Research, Inc. (MRI). In addition, an aircraft to
measure aerosols will be provided for the limited time of mid-JWle
to mid-July. 'nl.is aircraft. a 8-23 provided by the -University of
Washington, will also be utilized on some cloud physics missions.
A fourth aircraft. a Piper Aztec operated by Colorado International
Corporation. will be a combination cloud survey and seeding plane.
The survey missions will measure updraft profiles and tellperatures
at a large sample of cloudbases. It will also measure the moisture
. distribution in the subcloud layer.
The 1DOst important measurements for the microphysics studies
involve measurement of (1) the ice phase. (2) the liquid phase.
(3) the dynamical history. and (4) the nuclei of the cloud. Our
cloud seeding theories involve the introduction of appropriate
nuclei to increase the concentration of ice crystals at some tea­perature,
....hich then grow at the expense of supercooled ....ater. or
to increase the concentration of large droplets .....hich llay then
collide with and collect the Slll8ller cloud droplets. Questions
....hich should be answered before testing seeding hypothese are:
(1) are there adequate ice crystal or large water drop concentra­tions
(or nuclei to produce them) already present naturally; (2) is
there sufficient supercooled water from which the ice can grow; and
(3) is the cloud-droplet spectl'Ull broad enough to allow collision
and coalescence to proceed to produce precipitation drops?
The instrumentation on all aircraft is listed in table 1.
II-2
(
Table 1. - MQaswoed parameters of RIPLEX aircraft systems
Aircraft mission Cloud
f.leasurement Source Cloud Cloud Aerosol Survey
top base
time T T T
al titude-pressure T T T
-radar
airspeed T T T
heading T T V
position-VOR/DME T T V
-VLF T
rate of climb Ball T
angle of attack T
pitch T
roll T
accelerometer T
manifold pressure T
engine rpm
air temperature T T
dew point temperature T T
turbulence MRI T
liquid~water' content JI< T
NOM
drop spectra Pf.IS-ASSP
PMS-cloud
PMS-precip
ice concentration Turner-Radke T
foil impactor MRI P+T
bulk water
decel!erator-impactor (ice)
ice nuclei filters
f.lee 140
NCAR T
aitken nuclei T
nuclei spectrometers Royco T
CCN Mee 130 T
electric field T
events V+T V+T
photos-forward p
-side
-radar
voice recorder
computer tape recorder
(record type: T '" computer tape. P '" physical record. V '" voice tape or notes.
X '" not yet determined)
11-3
CBI Ctoud Top Ail'craft
The CSI cloud physics aircraft (Aero Commander 680 FL) has
instruments to record the location. altitude. and performance
of the aircraft. the standard dry-air properties. turbulence,
ice nuclei. and cloud particle (liquid and solid) properties.
Table I gives a list of these instruments. Much of the data
will be recorded on magnetic tape; other records will be foil,
ice crystals preserved in cold hexane and later photographed,
'and other photographs.
Several of the microphysical instruments will give comparable
data. Intercomparisons between such instruments provide a
partial check on the validity of resulting measurements. Also.
a degree of instrument redundancy is useful in cases of fail­ure
of a particular system.
The phenomena under investigation are discussed in the follow­ing
subsections.
The Ice Phase. - The ice phase of the cloud can be described
by the crystal concentration, sizes, and shapes. The CSI
cloud physics aircraft will have instrumentation (with some
redundancy) to determine these parameters.
II-4
(
c
The ice crystal concentration will come mainly from the
modified Turner-Radke laser-crossed polaroid electronic
counter with readout on magnetic tape. The instrument
counts only ice particles and not water droplets. Ice crys­tals
aggregated into flakes-would probably receive only one
count per flake.
Backup or cross-reference i~struments for crystal concentra­tion
will be the Particle Measuring Systems (PMS) large par­ticle
spectrometer (under the assumption we are looking at
ice only), the foil impactor, and the decellerator single­slide
ice crystal sampler using cold hexane. The spectrom­eter
provides electronic counts recoded on magnetic tape.
The foil impactor and hexane samples of ice crystals require
laborious visual analysis.
The crystal size can be determined electronically by the PMS
large particle spectrometer tmder the assumption that there
are no large water drops. Size information can also come
from the decellerator-sampler after visual examination.
Some crude size information may be available on the foil
impactor.
11-5
The crys'tal shape is obtainable only from the decellerator­sampler
after visual examination.
Ice crystal presence can be indicated inside clouds by inter­ference
with radio communication and sometimes by optical
indicators such as haloes.
The Water Phase. - The water phase can be described by a size­concentration
spectrum. This spectrum may be integrated to
provide a liquid-water content. a rainfall rate. and a radar
reflectivity. An air-temperature measurement will indicate
its degree of supercooling. Riming on surfaces viewed by
cameras crudely indicates amounts of supercooled wat,er.
The size-concentration spec.trum will be measured optically
by three PMS spectrometers. The ele.ctronic signals will be
recorded on magnetic tape. Two spectrometers size by. means
of optical arrays of photodiodes; the other measures by
optical scattering. The foil impactor. provides a b.~ckup
device for large drops. 'The decellerator-sampler m.ay also
give some infonnation.
The. liquid-wa.ter c,on-tent will be meas-ured, direct I}:'· b.y two
different hot-wire. deJdces (Johnson-Williams and a N.ational
It-6
Hurricane Research Laboratory prototype) and can be compared
to the calculations derived from the spectrum measurements.
The Dynamical History. - Most of the dynamical history infor­mation
will be gathered by the· photographic and radar systems
to be described. TI\is provides cloud exterior dimensions as
a function of time (and thus age of various portions of the
cloud).
Updraft information can come from the rate-of-climb instru­ment
accelerometer. altimeter. and air speed indicator if
the aircraft power settings are constant.
Turbulence probes will give diffusion and convection.
~. - Ice nuclei will be measured by a rotating
membrane filter device. and by a NCAR acoustical counter
operated at a constant reference temperature of minus 200 c.
No measurements of cloud condensation nuclei from the C51
aircraft are currently planned. Relevant infonation can be
obtained from the srnall droplet spectror.:leter if the aircraft
is operated just above cloudbase. The direct measurement
II-7
should be better than calculations from a nucleus spectrum
obtained from a counter operated at only one supersaturation
value.
MRI ctoudbase Aircraft
The MRI cloud physics aircraft (Piper Navajo) has instruments
to record location, altitude. and performance of the aircraft,
the standard dry air properties. turbulence. CCN. and liquid
cloud particle properties. Table I gives a list of these
instruments. Much of the data will be recorded on magnetic
tape; other records will be foil, photographs. and bulk water
samples. No ice-phase measurements are normally made by this
instrumentation. though the large PfolS probe could be used
WIder the assumption of no large water drops, and the foB
impactor could detect graupel and iC'e, crystals ~
The water-phase measurements involving" the PMS probes are the
same as for the C51 aircraft. No liquid-water content devices
are used on the,t-ffir aircraft. Instead~\ the ' PMS 'output is
integrated to provide this value. Bulk<\.ater samples can 'be
obtained.
DYlramicd measurements (updrafts. turbu'lence, 'cloud history)
are the' same: as,.£or CSI.
Ice nuclei may be measured by a Mee 140 ice nucleus counter (modi­tied)
and by Millipore filters. Cloud condensation nuclei will be
measured by a Mee 130 counter and will be verified by using the
PMS-ASSP probe just above cloudbase.
Aeroso~ Aircraft
The University of Washington's 8-23 will be used from mid-June to
mid-July to measure the aerosol properties of the air. The aircraft
is equipped with an automatic cloud condensation nucleus counter,
and can sample aerosols isokinetically over a size range from 0.003
to 100 Ilm; It also is possible to analyze large aerosols for major
element constituents. In addition, the aircraft is equipped with a
large number of cloud physics instruments.
survey and Seeding Air-craft
At Miles City. the survey and seeding functions will be combined in
one aircraft. the Colorado International Corporation's Piper Aztec.
The aircraft is equipped to measure and record the following parameters:
1. Time 6. Rate of climb (-1500 to
2. Indicated air speed +1500 ft/min)
3. Altitude (0-25,000 ft) 7. Distance to a VORTAC
4. Temperature (-50 to 50°C) 8. Direction to or from a VORTAC
5. Dew point (-57 to +71 °C) 9. Liquid water content
II-9
An algorith is provided to compute cloud updraft vertical velocity
from the above parameters.
The seeding aircraft will be equipped to carry 24 TB-I burn-in-place
flares containing 100 grams (g) of Agi each, and 26 TB-2 droppable
flares containing 50 g of AgI each. The aircraft is equipped with
wingtip acetone burners whiCh will be utilhed as well. An onsite
modification of the aircraft will allow the dispensing of dry ice.
Seeding data reports will contain seeding times, locations, and
amounts of material used.
Aircraft Camera Sya t:ema
All four aircraft will have a time-lapse nose camera and a hand-held
camera for occasional photos. The cloud photographs, when com­bined
with time, location, and azimuth data, plus camera constants,
will yield cloud dimensions and their geographic locations. Repeated
photographs of the s3JIe cloud will trace its dimensional history,
giving information on cloud dynamics and clues to the microphysics
that produce the radar echoes. Cloud dimension and location infor­mation
can also indicate occurrences of mesoscale dynamic interaction
with neighboring clouds.
The time-lapse systems on each aircraft will be triggered by a
master clock at 6 seconds per frame. The nose camera will show
entry points of penetrations. For this purpose a super-8 camera
with about a 13-1DIl lens is adequate. The C8llleras should photo­graph
either a digital clock with at least 0.1 I'linute resolution
11-10
(
or a dial clock with a second hand. The clock must be properly
illuminated under both bright and dark sky conditions. A date
card and other data may also be photographed.
The hand-held cameras (35-1lIll film. 28-l:1Iil lens) will be used to
photograph clouds of interest at irregular intervals. They will
have a wider field of view and can be aimed directly at the
desired cloud. The x-contact of the shutter provides a signal
which may be recorded along with the time on magnetic tape.
Hand notes of photo time and direction of view wi 11 provide a
backup time record.
The hand-operated aircraft radar cameras wi 11 record radar
echoes prior to each penetration. The data will be used to
show the distance to precipitation at a known time and the
flight path relative to the precipitation. A digital or dial
clock of the sarn.e illumination intensity as the radar display
will be photographed. while the x-contact of the shutter could
produce an event signal for backup on the magnetic tape.
B. Radar Observations
For the Miles City experimental area, two C-band (one 5.4-em and one
5.3- an) radars capable of transraitting 250-kW peak power wi 11 be oper­ated
during the 1976 field season. The Skywater Radar 1975 (SWR-75)
II-ll
will be located near the Miles City airport and will be the primary
radar for data collection and operational control of the research
aircraft. The second radar. operated by the University of North
Dakota Department of Aviation. will be located 125 km east of Miles
City at Baker, Mont. Its location allows for the establishment of
a radar climatology downwind of the HIPLEX experimental area. This
information is to be used in designing a program for monitoring any
downwind effects from HIPLEX.
Both radars have a digital video integrator processor (DVIP) to con­vert
returned analog signals to digital values and record them on
13-mm (O.5-in) magnetic tape. The DVIP permits contoured log video
to be displayed in mUltiple shades of grey. thus allowing recognition
of varying reflectivities within an echo. The $WR-75 radar has
17 levels of contouring covering an as-dB range in S-dB steps, while
the North Dakota radar has 6 levels covering the range of its receiver
with a nonuniform interval~between levels.
The operating specifications for the SWR-75 are listed in table 2.
Further details may be obtained from appendix A or the SWR-75 Master
C-band Meteorological Radar Sys~em_Operation and Instruction Manual
available at Miles City headquarters or at the DAI....RM in Denver.
11-12
Table 2. - Gene:rat System SpeC'ificaticn8
Skywater C-band Radar (SWR-?Si
Input power:
Operating RF frequency:
Antenna beamwidth:
Minimum discernible signal:
Rainfall differentiation:
Operating mode:
Feed type:
PIf:
PRF:
RCVR noise figure:
Dynamic range:
IF frequency:
Range intervals:
Scope:
II-13
220 V. I phase. 50 or 60 ! 5 Hz
wi th voltage transients of
:! 15 percent of the applied
voltage with a recovery time
of 2 seconds and frequency
transients of ! 3 percent with
a recovery time of 2 seconds
5460-5650 f.ntz
I degree (4.62-m reflector)
-113 dBm (LOG)
-113 dBm (LIN)
0.25 Ilrn per hour at 250 km:
Meteorological analysis
Horizontally pOlarized
2 .s
207/414
2 dB
85 dB
30 MHz
125 km, 250 km. 500 km
A-Scope. PPI. RHI
An L-band (20-cm) radar system is incorporated into both the SWR-7S
and the North Dakota radar. Only the Sl'iR-7S is capable of recording
the location of three aircraft on magnetic tape along with the cloud
video frOlll the C-band system. Both radars will display all transponder­equipped
aircraft within the interrogation range of each radar. The
range limit of detection depends upon aircraft altitude and distance
in addition to the transmitting equipment in the aircraft.
The SI\'R-75 radar has two radio systems. One of the radios is an PM
two-channel UHF transceiver. During aircraft sampling, the aircraft
scientists and mission coordinator will use this radio to relate infor-mation
about test case selection and cloud parameters. The other
radio system consists of one lBO-channel and two 360-channel VHF air­craft
radios. It will be used by the flight controller to talk with
the pilots of the aircraft and monitor conversations they have with
Salt Lake City ARTCC. Details concerning the operating frequencies
are covered in the section on Support Facilities. The North Dakota
radar will be equipped with one 360-channel VHF radio.
A frequency shift reflector and a transponder wi 11 be tower mounted
near the Miles City airport to provide accurate checks of th~ azimuth
orientation and range calibration of both the C-band and L-band portions
of the SlfR-75 radar.
11-14
C. Surface Precipitation Networks
Surface rainfall data will be collected near Miles City in the sUlllJller
of 1976 for the following purposes:
(1) To provide rainfall data from a dense grotmd network, which
will be analyzed in conjtulction with data from two C-band radars
located at Miles City, Mont., and Baker, Mont. The objective of
the analyses \dll be to determine the most practical and reliable
means of evaluating rainfall for the future quasi-isolated cloud
seeding experiment. This may prove to be rain gages alone, radar
alone or, most likely, some combination of the two systems.
(2) To provide an independent test of Z-R relations developed for
the large precipitation network by using smaller network clusters
outside the main network.
(3) To extablish, under field conditions, the reliability of a
new "memory rain gage" system and further test the reHabi Ii ty of
the LANDSAT Satellite, formerly called the Earth Resources and
Technology Satellite (ERTS). rain gage system. The LANDSAT system
underwent initial field testing during the fall of 1975 and, there­after,
was somewhat modified to increase reliability.
II-IS
Four types of rain gage"s will be used to accomplish these objectives.
Two radio telemetry rain gage systems are being developed or modified
by Western Scientific Systems. Inc. (WSSI), of Ft. Collins, Colorado.
The first system stores rainfall data on a cassette tape at a central
station. At intervals the data are also transmitted from the central
station to the LANDSAT Satellite. The second system stores rainfall
data at each memory gage. Periodically. the data are transmitted
from the individual memory gages to a tape cassette package on board
a light aircraft. The third type of rain gage is the conventional
Belfort weighing rain gage. These will be collocated with a portion
of the LANDSAT rain gages and all the memory gages during the 1976
field season. The final type of gage is the nonrecording wedge-type
rain gage. These will be located at all recording rain gage
sites to provide at least the total rainfall between service calls.
This information will be useful in case of recording gage failure and
will provide a check on the accuracy of the other gages. Because of
their small size. wedge gages can be placed with their orifices only
350 nun above ground where wind-induced catch errors are limited.
The three types of recording gages planned for use during the 1976
field season will have a time resolution of 15 minutes and rainfall
resolution of approximately 0.25 nun (0.01 in).
II-16
Proirnary Rain Gage fretwork
The Miles City project has approximately 91 Belfort weighing rain
gages available for use during the 1976 field season. These gages
exceed National Weather Service specifications 450.2201 and 450.2203.
A primary network of 109 gage sites will be established using
73 Belfort rain gages and 50 LANDSAT rain gages. Fourteen sites
will have collocated LANDSAT. Belfort. and wedge~type gages while
the remaining 59 Belfort and 36 WroSAT gages wi 11 be collocated
with wedge gages only. The location of the primary network sites
~s shown in figure 1. Gage density will be one gage per 15.5 )cm2
(6 mi 2).
Selection of the primary network location was based on four
criteria:
(1) An expansion of the network used in 1975 to a least
100 sites was deemed necessary.
(2) It was desired to incorporate as many as practical of the
S5 rain gage sites used in the 1975 LANDSAT network into the
1976 network
II~17
(3) An area within reasonable range of both S-cm radars was
desired.
(4) An area with reasonable field access was mandatory.
When necessary, the S4 additional primary network sites will be
fenced to provide a 3.7 - by 3.7-m or larger square area to pre­vent
livestock abuse. All sites previously used are fenced.
Rain Gage clusters
Six rain gage clusters will be deployed during 1976. Each cluster
will consist of three gage sites in a triangular pattern 4 kIn on
a side (same density as the primary network). Three of the six clus­ters
will be centered B km NW." W. and SW of the outer boundary of
the primary network. The other clusters will be centered 16 kin NE,
E, and SE of the primary network. The locations and shapes of the
clusters are shown in figure 1. Each gage site will contain a
conventional Belfort weighing gage, a wedge gage and also one of
the new memory gages. The latter have not been field tested.
Selection of the clusters waS based on the following criteria:
(1) It was desired to sample storms generally upwind and down­wind
of the primary network.
tI·-IB
(2) Data from clUSters separate from the primary precipitation
network allow the development of independent Z-R relations for
comparison with those derived from the larger network.
(3) Clusters should be within reasonable radar range.
When necessary, cluster sites will be fenced to provide a 3.7- by
3.7-m or larger square area to prevent livestock abuse.
LANDSAT Rain Gage System
The SO gages in the LANDSAT system wi 11 be configured aroWld a
data central which will receive telem.etered data from the auto-siphoning
gages. The gages register each 0.25 rm (0.01 in) of
rainfall and have a time resolution of IS trinutes. A 780-km2
(300-mi 2) test area will be used with a rain gage density of
15.5 ltm2 (6 mi2 ) per gage. The I..ANDSAT gages will be located at
SO of the 55 sites within the 1975 "LANDSAT network." The location
of each 1975 rain gage site was carefully selected to provide good
"line of sight" radio-telemetry to the LANDSAT central station.
Therefore, assuming the LANDSAT gages provide reliable data
sources, rainfall data handling should be minimized during 1976
from this portion of the primary network.
II-19
Memory Rain Gage SY8tem
The memory gages are designed to provide a means to measure pre­cipitation
over large areas with minimum servicing. A network of
such gages would be particularly useful in the semirugged terrain
found in much of southeastern Montana.
The memory gages are physically and electronically similar to the
LANDSAT gages except that they store or "remember" the data obtained
during the past 256 time intervals (256 x 15 min :: 64 hrs ::
2.67 days). They transmit all the data in storage each 15 minutes.
Approximately every other day. the appropriate data collection
system will be carried by a light aircraft to a sufficient height
to be essentially" line of sight" to the memory gages. From .this
position the system will record the stored data from the memory
gages onto a cassette tape in a form compatible with the time­share
terminals of the CYBER-74 computer system based in Denver.
During 1976, 20 rain gages of the memory type will be available
for field testing. A determination of their reliability is of
prime importance. Consequently they will all be collocated with
conventional weighing gages (lS'in the cluster networks and 2 else­where).
They will employ a self-siphoning mechanism which acti­vates
for e,ach 0.25 rran (0.01 in) of rainfall, and will have a
time resolution of 15 minutes.
II-20
Hail pads will be located at all rain gage sites. Pads at all
sites will be examined during routine service visits and will be
replaced whenever hail dents are evident. The hail pads will
allow for exclusion of probable hail events from the calculation
of Z-R relationships. Pads will be constructed of O.025-mm (I-mil)
aluminum wrap covering a square of Dow Chemical type II) blue styro­foam,
305 mm (1 ft) on a side and 25 rnm (1 in) thick.
D. Rawinsonde Observations
Rawinsondes will be launched 6 days per week near the Miles City head­quarters
to obtain upper air data for daily operational use and for
postseason analyses. These data will aid in preparation of daily
forecasts necessary to schedule field operations. They will also
provide information for partitioning other data collected. as well
as input for cloud model development.
A \'leather Measure Corporation RD-65 rawinsondc receiver will be uti­lized
for data collection. This system uses a selsyn-driven parabolic
dish antenna to track 1680 MHz sondes to obtain upper wind information.
The receiver. antenna control unit, recorder. associated rawinsonde
calibration equipr.lent and a time-share computer terminal wi 11 be
installed and operated from an equipment trailer located approximately
0.3 km north of the Miles City headquarters in an area relatively
II-2l
free of power lines or other obstructions. The antenna unit will be
mounted about 1.5 m above ground on a leveling base located just south
of the trailer.
Oalloon inflation will be accomplished in a specially fabricated build-ing
located adjacent to the equipment trailer. Extra-large garage-type
doors on two ends of the building ..,ill facilitate launching the
sondes during periods of strong surface winds. The same building will
be utilized for storage of all expendable supplies.
E. Ground-based Cloud Condensation and Ice Nucleus Measurements
Measurements of cloud condensation nuclei (CCN) and ice nuclei (IN)
will be carried out 6 days per week at the Miles City headquarters.
Data obtained will allow concentrations to be related to airmass type
and source region, and time of year.
Studies during the 1975 field season have shown the near-surface
measurements of both IN and CCN provide a relatively good indicator
of concentrations available at and near typical convective cloud base
elevations.
Measurements will be conducted in the identical laboratory facility
utilized during the past season's work. Inlet sample air will ag~in
be drawn from the top of a 16-m tower.
11-22
Ice nuclei concentrations will be measured by drawing air samples
through O.4S-11m Millipore filters held in 37-rran plastic field monitors.
All Millipore filter processing will be conducted at NCAR under the
supervision of Dr. G. Langer, and are to be sent to him:
Dr. G. Langer
NCAR
P. O. Box 1470
Boulder. Colorado 80302
Cloud condensation nuclei will be monitored with a thernal diffusion
chamber of the type developed by Dr. P. Allee of the NOM's Environ-mental
Research Laboratories.
All CeM and IN saT.I.pling will continue to be coordinated with the
AtI:lospheric Nucleation Group at OCAR through Dr. G. Langer.
F. Ground-based Photography
A pair of Super-8-mm time-lapse cameras will be located about 5 km
apart and pointing towards the rain-gage network. They will take
stereo pairs of cloud photos for later dimensional analysis. besides
providing a continuous description of daytime cloud cover over the
rain-gage network. The cameras will have a 30· field of view.
They will operate from about 0600 to 2100 daily as controlled by a
24-hr time clock. Photos will be triggered by a synchronous motor
I1-23
timer once per minute on the minute as given by the WWV time signal.
Two clocks and a month card will be in view and will be illuminated by
a light bulb. The main clock will be a digital display which includes
the day of the month. I t has a synchronous motor and wi 11 be set a
half minute fast so that photos are not taken while the clock is
advancing to the next minute. The other clock will be a battery-operated
clock to indicate the correct time (less accurately) in case
of a power failure. Although the cameras will not operate during a
power failure it is desirable to know when the failure occurred and
how long it lasted. Film must be changed every fourth day.
The cameras. clocks. timers. and light bulb wi 11 be housed in a large
weather-resistant box containing a window. The boxes will be weighted
with cement blocks and possibly tied down as well to prevent" movement.
Landmark stakes will be erected in the field of view and their posi-tions
accurately determined. A~careful,sul'vey of all angles involved
in the stereo system is necessary for solving the stereo equations.
A 16-mm time-lapse camera site will be erected near the rawinsonde
site. It will be operated during case study 'periOds, buttotherwise
kept indoors. A I-minute timer will trigger' the camera· on:~the min­ute,
as determin.ed by the 1'II'N time..' signaL A·\digital clock,will be
in view wi.th a date card and will be illuminated by a light bulb.
Should the. rawinsonde· operatol's, forget to turn' off- the camera it wi 11
IH24,
be shut down automatically by a time clock at 2100. The entire lUlit
will be JDOlUlted in a small shelter on a turntable so that it can be
rotated to view the case study cloud. Landmark stakes will be erected
at surveyed directions to show the direction of view.
Personnel on the ground will have a 35-mm film, 28-rmn lens camera to
photograph significant cloud developments at irregUlar intervals,
making notebook recordings of the time and azimuth of each photo.
C. Satellite Data
A photofax satellite receiver will provide real-time satellite imagery
at the Miles City site headquarters. This imagery wi 11 consist of
!»IS/GOES sectors having 0.5 and I nmi resolution at subpoint.' These
data will be received every half-hour for appropriate sectors of inter­est
to HIPLEX. These data are transmitted from the Satellite Field
Service Station (Sf-SS) of the National Environmental Satellite Service
(NESS) in Kansas City. "lo. The available sectors of interest to HIPLEX
are shown in appendix J.
These data will be used to analyze important convective, mesoscale,
and synoptic scale features contributing to cloud development in the
area of interest.
Il-25
In addition to direct real-time photofax imagery. digital satellite
data will be available from the White Sands Missile Range during peri­ods
from 24 May to 7 Jtme, IS Jtme to 15 July, and 1 August to 10
August, 1976. These data will provide quantitative values of visible
and infrared radiance over all ItIPLEX sites. These data wi 11 be col­lected
and analyzed by personnel from Colorado State University (CSU)
tmder contract to the Bureau.
H. ''leather Data Systems for Forecasting
A substantial data base will be available at the Miles City headquar­ters
for forecast development.
Standard National Weather Service facsimile charts are available·
through a cooperative arrangement with the local Federal Aviation
Administration (FM) Flight Service' Stat-ion (FSS). Charts normally
obtained include: Surface, SSO mbar, 700 mbar, 500 mbar. 300 mbar.
SMS IR, vorticity analysis, and barot.ropic.. p-r.ogs. Other pr.o.ducts
may be obtained at the request of, the forecaster.
High-quality satellite imagery win be available onsite from a photo­facsimile
syst.em,. This ,tmit is capable of producing updated images
at 30-minute intervals if so desired.•
11-26
Surface and upper air observations. and a wide range of data reduction
and presentation programs are available through the facilities of the
Bureau of Reclamation's Environmental Data Network. The network con­sists
of (1) a central computer located in Denver; (2) the computer's
data base and programs to access. process, and display the data; (3)
a commtmications link with the National Weather Service's computer
system in Suitland, Hd .• to obtain updated infonnation; and (4) remote
tiDe-share terminals at field locations. The tine-share equipment
available to the forecaster at I-files City consists of a 3O-character­per-
second remote terminal and a plotter mit.
The data base in the systems consists of the fOllowing:
(1) All National Weather Service (NWS) radiosonde observations
for the contiguous u.s.
(2) All local radiosonde observations that have been entered into
the systeJ:I.
(3) Twelve- and 24-hour predicted gridded fields from the National
Meteorological Center limited fine-mesh model.
(4) Hourly surface weather observations west of 90· longitude in
the U.S.
11-27
(5) Aviation forecasts for selected stations prepared- by· the NWS.
(6) Area forecasts for much of the western U.S.
A variety of programs and models are available to analyte and present
the data in printed and plotted forms. These are described in the
Project Skywater Environmental Data Network users manual available
ansite.
Two Automatic Environmental Surface Observation Platform (AESOP) sta­tions
will be tested in the Miles City area during 1976. These sta­tions
will be used to supplement the somewhat sparse NI~S-FM surface
data-reporting stadons in the area. The platforms provide hourly
wind speed and direction. temperature. dew point. pressure. and pre­cipitation
data. The data are obtained. through' the GOES sa·tellite.
and will be available on the Enviro.nmental Data· Network. Stations
will be located at Bro,adus and J.ordan. Mont.
11-28
III. Operational Considerations and Procedures
A. Daily Field Operations
Genera~ Scheduling
Field operations during 1976 will concentrate on the afternoon and
evening period of convective activity. Intensive aircraft and
radar sampling of clouds. and serial rawinsonde launches. will be
possible anytime between 1300· and darkness (end of civil twilight).
Appendix G lists sunset times and civil tWilight times for Miles
City.
The field season will cOllUl\ence on April 22. 1976, which will be the
beginning of a 9-day "shakedown" period of !!! systems and proce-dures.
A checklist of all systems and a report to show operational
status at the end of this period will be prepared by the project
director. This period is not intended to be used to prepare for
the field season. Rather. all measurement systems should be in
place and fully operational by April 22. The last 9 days of April
are to be a full-scale "dry run" to discover any procedural or
• All times in this plan are in Mountain Daylight Time (MDT) unless
otherwise noted. MDT will be used as the official time for the
experiment and all times are .ilitary time (for example, 1200 is noon.
1800 is 6 p.m.• etc .• based on a 24-hour clock).
III-l
system problells that llI3y have been overlooked in planning and setup.
To the extent that such problems fail to materialize, this period
will be no different than the remainder of the field experimental
period, which will extend froll May 1 through July 31, 1976.
Throughout the April 22 through July 31 period, routine operations
will be scheduled 6 days per week. One day during each Sunday
through Saturday block will be declared nonoperational by the
project director by 1700 the day before. This day will usually be
based on a forecast (issued at 1645 the day before) of no suitable
weather for intensive sampling. However, the day off may be
declared whenever the project director decides it would be advan­tageous
for the experiment.
Certain field operations, lDOst" notably rain gage servicing. "'ill
usually be carried out on a Monday through Friday basis. In such
cases, the declared nonoperational day wi 11 obviously not apply.
However, the procedure of standing down I day per week, at the
project dire.ctor 1 s discretion. will apply to the following: csr,
MR!, aerosol, and survey/seeding aircraft sampling, radar sampling,
rawinsonde observations. and ice nuclei and cloud condensation
nuclei measurements. All these measurement systems will either
operate. or be prepared to operate if suitable cloud systelll.S
develop, on the other 6 days of the week. At least one rawinsonde
(0830) will be launched each operational day whatever the weather.
UI-2
Daily Schedule of Operationa
Table 3 lists the daily schedule of operations for the measurement
systems noted. Aircraft sampling missions may be flown anytime
from 1300 to dark. depending on availability of suitable clouds.
Normally. takeoffs will not be made later than 1.5 hours before
sunset. However. the project director may occasionally call for
night Illissions so that aircraft and radar crews gain experience
with nocturnal cloud systems and operations.
Debriefing Sessions
A debriefing will begin promptly at 1130 the Ilorning after each
a15510n flown by the cloud physics aircraft. An exception is that
the debriefing will be held 24' hours later if a nonoperational day
follows a mission. Debriefings will not be held if aircraft sam­pling
did not take place the previous day. or were limited to
routine survey aircraft and/or aerosol aircraft lIissions. However.
the project director may choose to use this period for a meeting
of key personnel in any case.
The purpose of the debriefing will be to discuss the strong and
weak points of the previous day's mission(s). and any possible
improvements in future mission effectiveness. The debriefing will
be attended by DAWRM scientists, and by each aircraft's scientist
111-3
Table 3. Daily operations sahedule
0800 Team 1- begins preparation for rawinsonde launch at
Miles City.
Baker rawinsonde operator and assistant-- begin prepa­rations
for rawinsonde launch at Baker.
0830 Daily rawinsonde launch at Miles City and Baker.
Electronics technicians for Miles City and Baker radars
begin routine calibration and maintenance.
1015 Miles City team 1 and Baker team reduce rawin, and
team 1 aids forcaster until 1200.
Forecaster prepares for 1200 briefing.
1130 Miles City radar operator 1 arrives and begins a volume
scan.
A Miles City DAWRM staff member checks for possible air­space
conflict.s with Salt Lake Air Route Traffic Control
Center. Debriefing session of key personnel freq~ently
commences.
1145 Miles City radar operator 1 phones radar summary to
forecaster.
Baker electronics technician phones radar system status
and radar sUlllllary to forecaster l s aid at Miles City.
Other member of Team I prepares Millipore filter for IN
sampling.
1200 COIIlIlence briefing, which includes forecast for 1300 to
1700 and 1700 to dark, and reports on operational
status of all systems. Team I takes 30-minute lunch
break.
1230 Briefing ends. Team 1 ready to launch rawin anytime
needed.
1'300 Aircraft ready for sampling anytime from now until dark
if needed. _.. Baker radar operator 1 on duty.
1450 Team 2- reports for daty and takes CCN measurements.
111-4
Table 3. - continued
1510
1630
1700
1800
1810
1940
2115
2130
2340
0040
TeaD 1 departs after briefing team 2. Team 2 ready to
launch rawinsondes as needed until 2015.
Second briefing of key personnel frequently called by
project director. Second forecast issued covering 1700
to dark today and 1300 to dark tomorrow.
Baker radar operator 2 reports.
Miles City radar operator 2 arrives.
Miles City radar operator 1 departs after briefing
operator 2.
Baker radar operator 1 departs.
Team 2 removes Millipore filter froll sampler.
Team 2 departs.
Baker radar operator shuts down radar and departs.
Miles City radar operator 2 shuts down radar and departs
if no echoes present within 125 lui; otherwise operates
set until 0200 .
.. Both team 1 and team 2 consist of a lead rawinsonde operator and an
assistant located at Miles City. These tealJls also assist the fore­caster
and aid in data reduction.
U Baker radar operators I and 2 and the electronics technician will
rotate in these positioRs.
u" Project director will schedule standby times based on forecast.
III-S
and pilot who flew during the previous day's mission(s). The person
in charge of each aircraft will be expected to bring a completed
checklist to the debriefing. It will indicate the operational
status of the aircraft, including all measurement and recording
systellS. If a debriefing is not held, the checklist will be
supplied to the project director at the beginning of the 1200
briefing.
Daily Bl'iefing Sessions
All available HIPLEX personnel are encouraged to attend the daily
briefing held in the briefing room at the Miles City site. It will
begin prolllptly at 1200 with a forecast for the period 1300 to 1700
and 1700 to dark. The project director, in consultation with key
personnel fro. each aircraft, will then decide the type(s) of
mission to be flown that day (if any), and the probable timing of
the mission(s). Depending: on circumstances, the project dir:ector
may choose to schedule a mission at a definite time, or to, place
aircraft and radar"crews on standby for either or both" the' 1300 to
1700 and 1700 to dark periods. Conversely, he may elect; to stand
down for either or both periods. He may call for a second, briefing
at 1630 in cases where lack. of suitable weather and/or' equipment
problems preclude a Illission- before 1700, but a later lIission appears
at least somewhat likely. The 1630 briefing will also cODllllence with
a forecast. DAWRN scientists, radar, and aircraft flight crews will
lII-6
be expected to attend the 1630 briefing unless involved in routine
cloud sampling (Le., cloud surveyor aerosol .issions).
As a minimum, the parameters listed below will be forecast at 1200
each operational day for the period 1300 until dark. To the extent
practicable. the 1200 forecast will treat the period from 1300 until
dark as two separate periods divided at 1700. The 1630 forecast
will then be an update for the period 1700 until dark. This prac-tice
will allow for IlOre efficient scheduling of personnel than a
single forecast for the entire period.
I. maximum surface temperature
2. wind velocities at the surface and 850. 700, and 500 mbar
3. types of clouds expected
4. time of first convective cloud formation
S. height and temperature of convective cloudbases
6. height and temperature of maximum tops of convective clouds
7. hei,ght of the minus 10" C level
8. potential for severe weather
9. timing, type (R, RW, TRW), and approximate amount of any
precipitation within the experillental area.
111-7
In addition~ a brief "word forecast." will be prepared describing
t.he general synopt.ic sit.uat.ion prevailing at. the t.ime t.he forecast.
is issued, and changes expected during the forecast periods.
An additional requirement of the 1630 forecast is that the outlook
for the following day from 1300 to dark be described. The purpose
of this forecast is to aid in determining which days should be
declared nonoperational. Thus, the probabil ity that tomorrow I s
weather will be unsuitable for experimentation (that is, blue skies
only) should be addressed.
Bakel', Montana, IhmzJind Site
A 5.3-cm digitized radar system will be operated at Baker, Mont.,
125 km east of Miles City, during the April 22 through July 31
experimental period. This unit, and a built-in rawinsonde system~
will be operated by the -University of North Dakota. The general
scheduling of the three· person crew at this downwind facility is
shown in table 3. This section "expands upon the act.ivtties at the
Baker Airport downwind s1 te.
As at the Miles City site~ Baker personnel will work 6 days per
week as'determined by the Miles City project director. "The radar
will be IIllUlned between 1300 and 2340 daily. after being'calibrated
each...norning. The radar and rawinsonde syste. status will be
111-8
phoned daily at 1145 to the Miles City headquarters. A summary of
echo coverage and current weather will also be furnished at that
time. Beginning at 1300 and extending through 2300, hourly surface
weather observations will be taken and logged. These will have the
same format as standard reports from FAA facilities. A volume scan
will be made each hour and half-hour during the 1300 through 2330
period until echoes are detected within 170 km of the radar. Con­tinuous
recording will then commence as described in the radar
utilization section.
The first daily observation of radar echoes within 150 km. or
visual hourly observation indicating the likelihood of precipita­tion
(e.g., towering cu, Virga) will be reported to Niles City
headquarters by phone. An exception is that such occurrences need
not be reported later than 1.5" hours before sunset as aircraft
missions will not normally commence any later.
One rawinsonde release will be made daily at 1745 as described in
the rawinsonde utilization section.
Airspace Coordination
Fifteen minutes before the daily briefing. a OAWRM staff member at
Miles City will check with the Assistant Chief, Salt Lake City Air
Route Traffic Control Center (ARTCC) to determine whether there
111-9
will be any conflicts for airspace with other users. If there are
any restrictions in either space or time. they will be reported to
the project director so any modifications necessary to the intended
llIission can be included in the briefing.
If a mission is planned. then at least 1 hour before the intended
takeoff of the first aircraft the Assistant Chief at ARTCC shall be
contacted. The time of usage, the number of aircraft involved. pre-liminary
altitude blocks and an inital location defined by VOR
radials and DME from the Miles City VOR will be conveyed to the
Assistant Chief. All pilots will be responsible for filing appro-priate
IFR flight plans in accordance wi th a letter of agreement
between the Division of Atmospheric Water Resource Management and
Salt Lake City ARTCC.
Suspension Cl'iteria
High Plains Cooperative Program. - Although the experimental
design for this research project has not been comple.ted. the
suspension criteria developed ..during previous cumulus '-research
programs have been tentatively "adopted and 'are included in the
program's .preliminary plan. Under these criteria:
(1) The project director may suspend seeding operations in
rany _situation in which he believes operations .II8Y cause or
IlI-lO
aggravate a threat to life. property. crops. livestock. wild­life.
or ecosystems. The Division of Atmospheric Water
Resources Management will be notified immediately.
{2} The project director at all times will be cognizant of
potential seeding effects in the project area and surrounding
region. and has the responsibility to suspend operations when
it could be perceived that project activities might create or
aggravate severe weather situations.
(3) Seeding operations will be suspended iuediately by the
project director when the project meterologist or the National
Weather Service:
8. Issues a severe weather watch or warning for any part
of the operating area. or
b. Issues a tornado watch or warning for any part of the
operating area. or
c. Issues a severe hail warning or watch for any part of
the operating area, or
II 1-11
d. An offiCial hydrology-oriented agency issues a flood
watch or warning for any part of the operating area or the
watershed(s) affecting or affected by the operating area.
A complete record of activities beginning 24 hours preceding
the advent of severe weather will be assembled illllllediately
upon recognition of a stress period and will be Ilaintained
throughout the period. This will include: Notes on subject
matter and times of pertinent warnings; communications with
local agencies; radar. photographic and visual records; mete­orologieal
data a,nd similar information sufficient to accu­rately
reereate activities during the period.
(4) Seeding also will be suspended when. in the opir'Lion of
local and State groups, additional soil moisture would be
detrimental to crops.
(5) Seeding may be suspended duroing certain periods of plant
growth or harvest._ and during eertain social activities, such
as county fairs.
(6) Research aetivities maY' be suspended in favor of drought­-
relief activities if local, State and Federal agencies con­sider
it desirable.
III-12
Possible Adverse Wide-area and Long-term Environmental Impacts
of Precipitation Modification. - Cloud seeding intended for
effect within the boundaries of a study area may. in addi tion,
affect the precipitation at a downwind distance and could con­ceivably
have adverse impacts there. The possibility is also
recognized that a limited period of experimentation in the study
areas may initiate ecological changes, the effect of which could
conceivably be felt for a longer tille.
Risks arising from this source have been assessed as posing no
short-tertii threat to the environment but as deserving further
study with respect to possible prolonged use of weather
modification.
Mitigating measures are taking the form of research to determine
the degree to which precipitation increases may cause environ­mental
impacts, both adverse and beneficial, and studies of pre­cipitation
downwind from experimental areas aimed at understand­ing
the magnitude and mechanisms of changes possibly caused by
seeding. As the results of these researches become available,
they will be incorporated into criteria for the design and
operation of cloud seeding experiments and applications.
llI-13
B. Aircraft Utilization
Examination of the radar observations and ground-based photographs
uken during the 1974 and 1975 seasons at. Miles Cit.y revealed t.hree
general t.ypes of cloud syst.ems associated wit.h rainfall. They are
(1) "cumulus," which range from ~solated to clustered to mesoscale
cumulonimbus, (2) "overcast," which includes stratus, altostratus.
strat.ocumulus. and altocumulus covering the sky and possibly contain­ing
embedded cumulus. and (3) "midlevel." which include altocumulus.
alt.ostratus, cirrus. and thick cirrostratus. possibly blending into
each other. but predominately at high elevations. The precipitation
mechanisms and efficiencies of these types are unknown for Miles City.
The "overcast" type produces most of the rain, but the seeding poten-tial
of all three classes is unknown.
The aircraft operations are mainly intended to define the cloud proper·
ties. Obviously, clouds must be examined where they are located. but
if suitable clouds are present, priority· will be given' to~the airspace
over the rain gage network and in'view of,the suifac'e'ti'me"::lapse cameras.
The CSI cloud-ptiysics aircraft i~ ':.0 examine the~detailed microphysics
of the cloud. and some of the dynamics in order to d'efine the" precip-itation
formation process and to give clues~to its- efficiency.
III-14
The Mal cloud physics a"ircraft is to define the inputs into the cloud
at cloudbase in teI1lls of temperature, moisture. nUclei, and updraft
speed and area; it is also to define the cloud outputs in the rainshaft
in terms of droplet spectra and concentrations, shaft area, and down-draft
speeds. The droplet spectra and concentrations can then be used
to help calibrate the radar.
The aerosol aircraft is to determine the concentrations, spectra, and
properties of aerosols in the ainaass and in the updraft. It will
have cloud physics instrumentation as well, and may at times be
diverted to cloud physics missions.
During calibration seeding experiments, the survey-seeder aircraft is
to dispense cloud seeding Jn8terlals in a manner prescribed by DAWRM
scientists. When it is on survey" missions. it is to exaJline a random
sllllple of cloudbases to determine updraft profi les, and base al ti tudes
and temperatures. The al ti tude and temperature of the base define a
wet-bulb potential temperature and can thus be used to identify the
moisture field.
Aircraft data will be used to satisfy two types of modeling needs.
Primitive numerical models of simple cumulus clouds now exist. They
need input conditions including cloudbase temperature, updraft area
and profile, and nucleus spectrum. For verification they need the
history of cloud-top altitudes. 1IU.imum updraft speeds, maximum water
111-15
I j
contents, droplet and ice spectra and concentrations. and rainfall
output at cloudbase. These parameters will be provided by the air­craft
measurements. Other inputs such as the upper air-tellllperature
profile and winds aloft will come frOIl rawinsonde measurelllents. Most
existing numerical models require input calibration measurements from
isolated simple cumulus clouds in an environment with IittIe wind
shear. The examination of the sample of data from the sUDlDlers of 1974
and 1975 suggests that such clouds infrequently produce significant
rain in the Miles City area. If this is true, development of more
sophisticated models may be required for operational use in future
seeding experimentation.
The other type of model is the conceptual IDOdel; it crudely describes
in words and a few numbers and graphs what the precipitation process
<ll)pears to be. Such conceptual mOO.els are used for clouds which are
too complex for the present state-of-the--:ar.t of numerical modjlls.
Most of the rain in Miles City falls frOIl such clouds. If they are
CWJlulus showers produc.ing signi(h::an.t rain, 'the clouds are usually
in interacting mesoscaJe clusters. S.kies which are o:verc.as.t produce
most of the area -rainfall and the details of what is happeni'ng above
cloudbase are unknown. The high !level precipitating clouds are also
an unknown system; no models, conc.eptual or nUlllerical. ·exi.st for them.
f'or the b_ulk .of the Miles City pre.cipitating sy.stems., the.re is insuf­ficient
data to adequately create even a conceptual IIIOdel. The
111-1.6
use of aircraft for the sUJ:llller of 1976 will be to obtain the Il.icro-physical
and dynamical data necessary to initiate conceptual and numer­ical
lllOdels of the precipitating systeJlS of the Miles City region.
Each aircraft crew will be expected to produce a preliminary paper
printout of selected data from selected times that were recorded on
the magnetic tape. This will verify the functioning of key instru-ments
and provide preli.unary results on the success of the tUssion.
These data will be expected by 1030 on the day following the flight.
However, if the tapes IIIJst be sent to Denver, a delay of up to 4 days
may occur before preliminary results are produced.
Table 4 itemizes the desired outputs. Part A describes a series of
data at I-minute intervals. This series is to show where the air-craft
is; the rawinsonde parameters of pressure altitude, temperature,
and dewpoint; and where the aircraft is going. A 3-hour flight will
require 180 lines of data or 9 pages on a line printer. Table 4..
part B describes a 6-second series; data during the intervening 5 sec-onds
are ignored in these preliminary results. If there are 30 minutes
of microphysics data, there will be 300 lines of print or 15 pages from
a line printer. The lines from the I-minute and 6-second series should
be interspersed so that only one reading of the tape is required.
These microphysical numbers are important by themselves for models and
climatology purposes. They may also be related to each other to show
Table 4. Data outputs ~at«i Ol'l J'I'lP8l" by 1030 on tM dIZfI [cHewing 8aah
flight (ilWol= as pl"lWtioabl4).
Pan A. - the 1-lIinute series (ianorine the other Sll seconds)
1. tille
2. azilluthfroliVOR
3.rangefrolllVOR
4. altitu40
S. air temperature
6.4ewpointtellperaturo
7. indif;ated(ortrue)
airspeed
8. headj,na
~
hr,lIlin, (see)
whole degrees
who1&nllli(or1l;TIl)
wholefeetorlletet's
tenths of "C
tenthsof"C
whole knots
(orll/sec)
whole degrees
~
16 (sef;onds.OO)
IS
IS
I3
FS.l
FS.l
I3
OaUlPOSitionsused: 33;seyen2Xspacesb..t_..nd.ata: 14;aini_line
width: 47 spaces.
Pan B. - the 6-second series Oporine the otber S seconds). This series
will be displayed. durine tilleS (anyone or 8. c:aabination of): 8.. of rate of
clild! Inater than I lI.s-1 while near a cloud; b. of counts on PMS 8.nd/01' lee
probes; e. between eloud entry and. cloud. exit event men,
2. altitUde
J. indicated (or true)
airspeed
4. airtelllperature
S. rateofeliab
6. PMSdroplet
concentrations
- .ssp
-cloud
-predp
7. PHS water contents
- .ssp
- clouds
• preeip
8. dBt
9. rainhllrate
10. iceconcentration
11. JWw:~:/~~t~~fid-
12. turbulence
13. icenuehi
hr,lllin,sec
hr••in,&tenths
....holefeetormeters
whOlek.nots
(orlll/sec)
tenthsof"C
tenths of Il/sec
~-,
liter- l .-,
II.'
IIII.·''
dB'
oo/h.
raw counts·
Optional Outputs
tenthsofg/Ill
'
rllweounts
~: ~~~~s
perCll3
"F6.1
IS
IS
FS.l
FS.l
"FS.2
IS
FS.J
FS.l
FS.3
IS
F4.1
IS
F3.l
IS
FS.1
IS
FS.O
Oata positions used: 80; seventeen 2X spaces bet_en data: 34; IIini_ 1iDe
width: 114spac<!!S .
• Counts no~lited for airspeed and slll:lple vol.-e lilly be substiruted and
expressed in per liter units for iee.
ice growth at the expense of supercooled water, the particle size
relative to updraft intensity, locations of precipitation within
the visual cloud and the radar echoes, the particle growths as
related to available growth time, signs of and rates of ice crystal
multiplication, rime accretion rates, crystal aggregation rates,
melting zone behavior, particle characteristics at the time of first
radar echoes and many other possibilities. l'lhen seeding materials
are introduced at known amounts, the effects of seeding on any of
the microphysics parameters can be measured directly to see if
the expected results were produced.
Two basic types of aircraft missions are planned for the 1976 field
season, these are:
Type A. Z-R study over the rain gage network (primarily cumulus,
but also includes some overcast and mid-level systems).
Type B. Cumuliform life cycle study (includes isolated, mesoscale,
and embedded clouds). It is estimated that approximately
SO, but definitely no more that 100, cumuliform clouds
will be seeded during the sUl1ll\er field season to test
seeding procedures and materials under actual field
conditions .
III-19
When precipitation is oecurring over the rain gage network, priority
will be given to mission type A. Mission type B will be emphasized
whenever precipitation is occurring soaewhere in the experimental
area but not over the primary rain gage network. However. the
.ission priority on any given day will be detennined not only by
the prevailing weather situation, but also by consideration of equip­ment
availability and nUlllbers of each mission tyPe already flown.
The aircraft availability is expected to be as follows:
CSI cloud physics
MRI cloud physics
aerosol
survey-seeder
22 April to 31 July
22 April to 31 July
15 June to IS July
1 June to 31 July
Individual missions of each aircraft are described in the following
paragraphs. Aircraft loeations during these aissions are sketched
in figures 2 and 3.
111-20
(
~
a) Typical "Figure Eight" - Two Perpelldicular Passes
b) Pattern Variation - Two Parallel Passes (used when Figure Eight
pattern not practical due to neighboring clouds)
[0", 50 omi]
[300", 50 nmi)
[60". 50 nmi]
HLS VOR
[240", 0 nmi]
[10". 50, om!)
[120". 50 nm!]
c) Example of survey aircraft flight pattern.
Figure 2. - Standard fligh't patterns for cloud penetrations
II;-21
;" ..
....
",
'...,
..........:
1-,
r~
:~, j;:. ... ~{l; ,,.:.' 'r /1
....,<. I "._1;.
..'t-
1-J,-- "'=;"
~
<If--?-r----~--__t___I\0> '" '-W'''
<:J- --t> A (when available)
to radar -E--
raIn gage network
(a) Z-R studies (S8 idle or elsewhere)
-pho1:0a...{:>S8
::;~;~l 4-+------+--t>CSI 1_100 "ff --!O~O
j J ,~- ..x:==~.....,..,-j_ -- -»--E--- »"
0{ ~MRI ~A
~ 21
A (b) cumul1form life cycle study
Figure 3. - Aircraft positions during missions for CSI, MRI, A-aerosol, and
ss-survey-seeder aircraft
CSI Cloud Physics Aircraft
Z-R and Cwnulifol'trl Ute Cycle Study fMi.Bsion types A and B)
The aircraft is to climb to the minus 10·C level, located at
approximately 6 km*, allowing about 40 minutes for the climb.
The ascent should pass through as many clouds as possible to
provide extra lift and to provide extra random cloud samples.
The flight path should be in the direction of the expected
working area, and in formation with other instrumented air-craft
for as long as practical. The 40 minutes is sufficient
time to get to any location within the lSO-km radar range.
Once at altitude, the mission coordinator on board the C51 aircraft,
in consultation with personnel at the radar, will select a suitable
test case. Attempts will be made to select growing turrets as they
approach the minus 10·C level. After the turret passes about 300 111
above the aircraft, it will begin to penetrate the cloud, and will
repeatedly penetrate the same systell for the life cycle of the cloud
or until safety c~nsiderations or the aircraft scientist recOllllllend mov-ing
to a different cloud. Penetration directions should alternate
• All elevations in this plan are referenced to lIean sea level (asl)
unless otherwise noted.
111-24
(
between parallel and perpendicular to the shear vector, approxi­mately
according to the figure-eight pattern in figure 2a, until
the airspace becomes too cluttered with nearby and especiallY
unsafe clouds. The pattern of figure 2b may then be used. The
aircraft should maintain as 'lIIJch as possible an attitude for
level flight in still air so that updraft measurel:l.ents may be
most reliable. Altitude adjustments back to the minus 10°C level
are to be made after penetrations.
This flight procedure is the same for both natural and seeded
clouds. If clouds do not reach the minus 10°C level, a lower
flight level will be assigned. The aircraft will return to base
when directed by the mission coordinator or dictated by the fuel
supply.
MRI Cloud Physics Aircraft
Z-R Study (Mission type A)
The aircraft will depart with the CSI aircraft and proceed
towards the rain gage network, staying in formation for as
long as practical. The MRI aircraft will then descend to
sample rain in the radar beam tilted 1 degree above horizontal.
A map of the elevations of the beam over the network will be
provided upon arrival at the site. The aircraft track will
preferably be along VOR radial 041 0 over a line of gages marked
with fluorescent orange panels or along the VOR radial passing
over the Illinois State Water Survey (151'1'5) ground disdrometers.
If the rain is falling only over other gages, the track will
be through the rain in a radial direction. In general, the
aircraft will climb as it flies away from the radar and descend
as it returns to stay near the center of the radar beam.
CumuUfonn Life Cycle study (Mi88ion type B)
The aircraft will depart with the CSI aircraft. flying in the
direction of expected operation and clillbing to cloudbase.
The climb may take as long as 15 Jrinutesj total travel time
to the area of interest may be as long as 30 minutes.
After selection of a test cloud by the mission coordinator.
the MRI aircraft is to first fly about 300 m above c10udbase
in the updraft. making two perpendicular passes according to
111-26
(
(
the figure-eight pattern in figure 2a. It is then to descend
to between 100 and 300 m below cloudbase in the updraft and
continue to make figure-eight passes. Once rain begins to fall
from the cloud, the aircraft is to sample the rainshaft in the
figure-eight pattern until either the rainfall ends or the
mission coordinator recommends moving to another cloud. If the
cloud is raining upon arrival, the updraft passes below cloud­base
are to be omitted. However. the penetrations about 300 m
above cloudbase will still be made. These updrafts may be
sampled as a byproduct during the necessary aircraft maneuver­ing
outside of the rainshaft. Flight patterns are the same
for both natural and seeded clouds.
Aerosol Aircraft
The aerosol aircraft will generally make a daily vertical sample
of aerosols up to at least 5 km (usually above the haze layer)
during the afternoon. It will operate up to 7.5 km when employed
for cloud penetration work, both with seeded and non-seeded clouds.
This aircraft may also be used to substitute for either the "lRI or
111-27
CSI cloud physics aircraft if they are ever unable to operate for
any particular mission.
Z-R and eumuU.fom Life Cyete Study (Mission types A and B)
The aerosol aircraft will sample aerosols in the general vicinity
of the case study cloud. At ranges greater than 15 kill from the
case study cloud the aerosol aircraft may penetrate other cloud-bases.
However, whenever the aerosol aircraft is wi thin 15 km
of a case study cloud, it will maintain at least 1,000·m vertical
separation frOlll d\e case study eloudbase unless it has visual
contact with d\e MRI aircraft. In this case it Dlay operate up (
to 300 III below the MIt! aircraft. In some cases, expecially for
seeded clouds, the aerosol aircraft may be requested to pene-trate
the rain shaft below cloudbase or the cloud above the C5I
aircraft at about the _15° to _20°C levels. In such cases the
aerosol and MRI aircraft pilots, or the aerosol and CSI pilots.
will coordinate their rain shaft and/or cloud penetrations such
that either a vertical separation of 1.000 III is maintained or
only one of the aircraft is in the rain shaft and/or cloud at
any time.
(
III-28
When rainfall is occurring over the rain gage network, MRI
is to fly in ~he one degree tilt radar beam. for a Z-R study.
This may be transformed into an evaporation study as well by
having the aerosol aircraft fly above MRI at c1oudbase. The
rain will then be sampled at cloudbase, in the 10 beam approxi-mately
half way between cloudbase and the ground. and at the
surface.
Survey and Seeding Aircraft
Survey Missions
The survey aircraft will fly a prescribed flight pattern. such as
the hexagonal pattern illustrated in figure 2c, over known land­marks,
departing from such a route to fly under nearby clouds.
It will fly under the cloudbases, maintaining an aircraft attitude
and performance appropriate for level flight in still air. It
will fly one figut:'e-eight pattern, or a single straight pass if
the figure eight is impractical, under each c10udbase that is
sampled. When between clouds, the time, position, and elevation
will be recorded with a frequency that will penlit reconstruction
of the flight pattern such that the time and location of changes
in the continuously recorded temperature and dew point values can
be noted. In consultation with the aircraft coordinator (MRI
pilot). this aircraft will normally maintain a hori zontal separa­tion
of at least 15 km from intensive case study clouds, unless
involved in seeding such clouds.
Seeding Missions
Z-R and eunruUform Life Cycle Study (Mission types A and B)
The seeding aircraft will drop dry ice, burn or eject flares.
or operate acetone generators, as directed by the mission
coordinator. This seeding will occur (1) at or just below
cloudbase (after MRI has withdrawn fr01ll that airspace and is
in clear air). (2) at the O· to minus S·C level (while CSI is
in clear air), ·or (3) from a level above or near cloud top
(while CSI is in clear air). Burn-in-place flares or acetone
111-30
generators will be used at levels (1) and (2). droppable flares
will be ejected at level (3). and dry ice lIay be dropped at
levels (2) and (3). After seeding is accomplished, the seeding
aircraft will withdraw froll the cloud. It raay be directed to
maintain a position a few to several kilometers away froll the
seeded cloud while the crew takes still photos of the cloud and
carefully records the times of the photos and 3-D positions of
the aircraft. In general, somewhat heavier seeding may be con­ducted
during the early months until confidence is achieved in
detecting the resuaing ice nuclei and ice crystals. Seeding
rates may then be reduced.
Decisions
The mission decisiorunaking process will typically follow the follow­ing
sequence: Once suitable clouds for sampling are believed to be
developing, the mission coordinator will request that the aircraft
depart. The miss.i,on coordinator will fly in the CSI aircraft. Once
airborne. the mission coordinator. in consultation with scientists at
the radar, will select a portion of the experimental area for the
III-31
initial investigations. Aircraft operations will generally be con­fined
to a ISO-loa radius of the Miles City radar. Once at the
region of interest. the Ilission coordinator will select a particular
case study cloud from visual observation, and will report its posi­tion
'to the CS1 pilot, who will relay the position of the cloud to
the other aircraft pilots. with help from the aircraft controller.
The mission coordinator. in consultation with the scientist on
board the other aircraft, will decide when to cease sampling the
cloud and to proceed to the next cloud or return to base. Any
particular type of aircraft operation (for example, cloud pene­tration)
will be terminated by the pilot in cOlllll8nd whenever, in
his opinion. carrying out that operation would be huardous. The
project director will be notified of such tenaination, but it is
not necessary that the pilot discuss the situation prior to termi­nating
the operation. The pilot is in the best position to aake
such decisions and has the authority and responsibility to take
whatever action is necessary to insure the safety of his crew and
aircraft.
II1-32
(
The pilot of the MRI aircraft will coordinate each aircraft's
position by radio conversation with the other pilots and Salt
Lake City Air Route Traffic Control Center to insure safe separa­tion
is always maintained among all aircraft.
Calibration
During the start of every mission each aircraft will pass directly
over the radar prior to departing to its area of operations. The
cloud physics and aerosol aircraft will record their position on
their data systems. while the cloud survey aircraft will note the
DME and VOR readings on paper or voice tape. The time of visual
passage over the radar must be noted to the nearest second by all
aircraft with other than manual recording systems.
Every day as any aircraft is returning to base. it will be required
to fly visually over one known landmark. A list of landmarks to
be used will be provided to each pilot upon arrival at the HIPLEX
site. The list may be supplemented by photographs. One pass over
lII-33
the landmark is to be at constant distance from the VOR. while
another pass is to be made flying over the landmark radially towards
the VOR. Hand notes are to be made identifying which landmark it
was, and passover times are to be noted accurately. The cloud
survey aircraft will make hand or voice notes of the VOR and DME
readings each time it is just above the landmark. Each aircraft
is then to fly over the radar, again noting the time (or DME and
VOR readings for the cloud survey aircraft). The aircraft may
then land.
By 1030 on the morning of the next operational day following the
flight, hard copy navigation outputs from the data recording systems
will be required at approximately 6-second resolution for all times
within 0.5 min of passing over the VOR or landmark. The apparent
coordinates of these positions will then be checked for accuracy.
Survey aircraft crews will provide hard copies of their written or
voice tape notes by the same time.
All aircraft data systems will record the air temperature and dew­point
(if available) during the landing while the aircraft is within
III-34
(
10 m of the runway, and. preferably. just before touchdown. The
indicated pressure altitude just after touchdown is also to be
recorded. After the aircraft lands. one of the crew m'embers is to
make a special reading of the FAA instruments to determine the sur­face
air temperature, dewpoint, winds, and altimeter setting. Such
a special reading is to be made within 5 minutes of landing and will
be used to help verify the calibration of those aircraft instruments.
These and other instruments will also be calibrated according to the
normal procedures for those instruments. by tower fly-bys when possi­ble,
by formation flights with other ai~ra:ft, and by ascents in air
being measured'by a rawinsonde. Instruments will be assumed to be
uncalibrated Wltil thus proven. Some calibration experiments that
will be requested at Miles City are listed in appendix E.
III-35
C. Radar Utilization
Mites City Radar
The SWR-75 radar located near the Miles City Airport will be manned
from 1130 through at least 0040 6 days each week. If echoes are
present at 0040. operation will continue until 0200. Anytime pre­cipitation
echoes exist within 150 km of the radar, they will be
recorded on magnetic tape for detailed computer processing by the
Bureau of Reclamation CYBER-74 computer facility in Denver.
Two radar operators, an electronics technician, the mission coor­dinator
and the aircraft controller constitute the onsite personnel
responsible for maintaining and operating the radar system.
The electronics technician shall perform a complete electronic
calibration of the radar system on the morning of each operational
day (6 per week). This calibration shall strictly adhere to the
procedures described in appendix D. The technician shall daily
perform preventative maintenance and any needed maintenance tasks
and attempt to have the system ready for operation by 1130. If
any malfunctions will cause a delay in availability of the radar.
the project director shall be notified immediately and briefed on
the nature of the malfunction and the anticipated time that the
system will become available. All calibration data must be logged
on the appropriate forms. One copy of the calibration data will
be in the radar and another copy will be sent to Denver at the
time the tapes are mailed. The calibration procedures are listed
in appendix D. Also described in appendix 0 are procedures for
sphere calibration of the radar system. This calibration shall be
accomplished during the months of April and June and again during
the first half of August.
Before initiation of any data recording. the radar operator shall
complete the checklist of appropriate switch settings which con­trol
the manner in which data are recorded and displayed. These
are the 2!!.!l. switch settings, and hence only mode. to be used for
recording radar data. If for any reason the radar data is recorded
in anything but the normal JDOde. this information should be logged
on a form which lists the following information.
1. TAPE LD.
2. Begin time and record count
111-39
3. End time and record count
4. Reason for deviating from standard data collection mode
5. Switch settings changed and their values
The above information should be given for each appropriate block
of data so recorded. One form should be filled out for each tape
containing nonstandard data. This form should be firmly attached
to the corresponding tape prior to shipment to Denver. A copy of
the checklist is included in appendix B. One is referred to appen­dix
A for a discussion of the full range of capabi li ties of the
radar.
After the checklist has been completed, the transmitter shall be
turned on and the radar will be used for surveillance to a range
of 250 km. While in the surveillance mode, one volume scan to 130
will be taken twice per hour, on the houT and 30 minutes past the
hour. This scan wi 11 be recorded and wi 11 be noted in the Radar
Log Book. Its purpose will be to detect any echoes within 150 km.
Once echoes exist within ISO km. recording of 130 volume scans
(requiring 5 minutes) will begin iDUllediate1y at exactly the appro­priate
2, 7, 12. 17 ..... 52, and 57 minutes past the hour. This
11-1-40
"matches" the 1· scan with the rain gage data. The radar digital
clock is to be set by WWV before recording cOllll1ences.
By 1145. the forecaster will be briefed concerning the location.
size. shape and maximum intensify of any echoes that exist. If
no echoes exist, the radar shall continue to be operated in the
surveillance mode until 1230. At this time the mission coordinator .~ I
will brief the radar operator concerning the forecast and provide
any special instructions for further radar operations. Notes con-cerning
the briefing to the forecaster and from the mission coor­dinator
will be placed in the Radar Log Book.
If a research flight is planned, the mission coordinator and the
aircraft controller will report to the radar at least 15 minutes
prior to the intended takeoff of the first aircraft. Both the
tliF and VHF radios in the radar and aircraft will be "ground
checked" prior to takeoff. The aircraft controller will determine
the assigned IFF transponder code for each aircraft and set that
code into one of the three sets of thUJllbwheel switches for record­ing
the aircraft location.
I f recording of echo data has not been in progress prior to the
takeoff of aircraft, the sequence of 5-minute, 13· volUJl1e scans
III-41
will begin at this time and continue throughout the duration of
the flight even if no echoes occur. Thus, a radar tape will exist
for the duration of every research mission, even if echoes do not
develop. If echoes continue to occur after the flight, recording
will continue until either no echoes are present within ISO km or
at the scheduled shutdown time.
Two tape recorders are furnished with the radar. Al though the sys­tem
is designed to switch automatically to the other recorder when
one tape is full, the data processing procedures require complete
scans on a given tape. Therefore. it is necessary to change record­ers
manually when one tape nears its record capacity. The record
count should be monitored, and when 12,500 records have been
recorded (one tape will hold slightly more than 13,000 records).
the switch to the other recorder should be made at the completion
of the volume scan in progress. The best way to note the end of
a volume scan is to observe the elevation angle being displayed.
It will increment upward by 1° from 1.0 through 13.0 and remain
at each degree for about 20 seconds during the volume scan. At
completion, the elevation angle will decrease rapidly to about
0.7° as set on the elevation angle handwheel. When this occurs,
at least two end-of-file (EOF) marks should be placed on the full
tape by depressing the EOF switch on the digital control panel, the
111-42
record count should be reset to zero and the tape recorder not in
use should be selected by depressing the appropriate switch on the
Digital Control Panel. Each tape will be labeled ",ith the Julian
date, sequence code, start and stop time and beginning and ending
record count. The exact procedures are described in appendix C.
Proper entries shall also be made into the Radar Log Book to doc­ument
all tape changes. The only exception to the above discussion
",ill be in the event of a power failure or purposely turning off
the main power to the system. Anytilte the main pever to the system
is interrupted, the tape being used for recording is to be removed
and properly identified and a ne", tape is to be used for further
recording.
All tapes recorded for a given day shall be left in the workshop
area in Betal tape mailing box"es. The technician ",ill deliver all
tapes recorded the previous day and a copy of the calibration data
to the project secretary after the calibra'tion has been completed.
The secretary will make a log of all tapes and the date they were
mailed to Denver. The secretary will be responsible for promptly
mailing the tapes with the appropriate calibration data included
in the same container.
During a research mission, the aircraft controller will monitor
the project VHF frequency (118.55 or 122.9) and the VH~ frequency
III-43 ~
assigned the aircraft for contacting Salt Lake City ARTCC. All
cOllllllUnications between the aircraft controller and the pilots of
the aircraft will be on the project frequency. The pilots will
also use this frequency when it is necessary to coordinate the
location of one airplane with respect to another. The mission
coordinator will communicate with the aircraft scientists or
observers in the aircraft on the lIHF radio. The mission coordi­nator
and aircraft controller, and the aircraft scientist and
pilot, will utilize voice communications to complete the link in
all necessary coordination of the acti vi ties.
Ultimate responsibility for maintaining safe separation distances
will rest with the pilots during nonstandard formation flights
operating under provisions of required regulations while performing
their mission in conformance w'ith. an ATC clearance. The Salt Lake
City ARTCC will issue all clearances and must approve any devi­ations
requested.. The aircraft controller in the SWR-75 radar will
provide navigation assistance only to the extent of aircraft loca­tions
relative to cloud echoes and information concerning maximum
reflectivity values and the horizontal extent of cloud echoes. At
no time will the aircraft controller attempt to exercise "terminal
control" guidance of the aircraft.
The radar operator will be responsible for entering operator note­book
entries to the data tape during intensive case study flights.
III-44
The mission coordinator will supervise the radar operator to assure
pertinent data entries are made. The coded entries and a brief
explanation of their meaning is presented in figure 4. The exact
manner in which they will be routinely used will evolve as experi­ence
with the system is gained.
Bakel" Radal"
A C-band digitized radar will be operated at Baker, Mont., approx­imately
125 km east of Miles City (see fig. 1). This radar will
be operated by Universi ty of North Dakota personnel and will be
primarily concerned with possible downwind effects attributable to
HIPLEX. It will be utilized primarily for data collection, which
will be processed by the University of North Dakota computing facil­ity
with l:i.ttle emphasis on real-time interpretation of data.
One electronics technician and two radar/rawinsonde operators will
be the only personnel available. They will operate on the same
6~day week as the Miles City radar and aircraft crews. The antic­ipated
period of radar data collection will be from 1300 to 2340
each day, with one daily rawinsonde released at 0830. The routine
work schedule is given in table 3.
A complete electronics calibration is to be performed on the morning
of each operational day strict ly according to the procedures of
111-45
~ 2 3 • 5 6 7 8 9 rJ IsuSreveedyl ~'0' ~Entry [E;xJit ~Base ~Mid ~Top
10 11 12 13 " 15 16 17 18 EB E:J ~ ~ EJ ~ ~ E:J E:J Range
Button:
1-4 individual aircraft
5-6 cloud penetration data
7-9 seeding data
10 case muaber
11-12 start and stop times (penetrations, seeding, updrafts)
14 temperature at a given altitude. Thus temp. would always
be associated with an aircraft and altitude
15 azimuth and range to the center of the case
5 digits: 320 26
AZ Range
16 rain observed intensity: 0 '" none, 1 .. virga. 2 .. light
rain. 3 .. moderate rain, 4 '"
heavy rain
17 other: any other message which must be written into Radar
Log Book
Figure 4. - SWR-75 op_erators notebook
trI-4'>
appendix D. A copy of the calibration form should be sent to the
University of North Dakota with each shipment of data tapes. Pre­ventive
maintenance shall also be performed each morning, and other
maintenance as soon as practical after any system failure. Sphere
calibrations (see appendix D) shall be performed during April, June,
and the first half of August.
As discussed for the SWR-75 system, this radar will also be operated
in the surveillance mode with a volume scan each hour and half hour
until echoes exist, in this case within 170 km of the radar. When-ever
echoes are closer than 170 km, repeated volume scans will be
taken until all echoes completely dissipate, move beyond 170 km,
or 2340 hours occur.
Because the downwind radar does not have automatic control of eleya­tion
angle stepping of the antenna, the operator will have to man­ually
step the antenna elevation by 10 increments for recording a
volume scan. The radar does not discontinue recording while the
antenna is in transit from one elevation to another. Therefore,
the operator will have to choose a portion of the area in which
to make the elevation steps. Ideally, the area should be echo
free, but if this is not possible the antenna should not be stepped
while it is oriented over the rain gages.
11[-47
Because volume scans require continual manual operation, one will
not be recorded every 5 minutes. Instead, a 16° volume scan will
start at IO-ainute intervals beginning at 2 lIinutes after the hour,
as determined froJQ WHY; a 1° "A scan" will be recorded at IO-minute
intervals, beginning at 7 Ilinutes after the hour. The 16° scan
will start with the LOo "A scan," followed by 1.5° steps to 2.So,
4.0°,5.5°, etc., up to 16.0°. Since the downwind radar has only
one tape recorder. the tape changes should be scheduled to coin-cide
with completion of the 1.0° "A scan." Volume and "A scans"
should always be started exactly 2, 7, 12, 17, etc., minutes after
the hour as determined from WWV. As with the SWR-75 radar, only
the switch settings noted in appendix A are to be used during !!!l.
data recording.
The downwind radar has an addi'tional PPI that has independent range
selection from the master console PPI. The additional or remote
PPI has a super-8 movie camera J:lo.1Jnted to take time-lapse photo-graphs
of the cloud video, date, time and ant.enna eleva.tion angle.
The system was designed such that a frame was expo,sed at I-minute
intervals. It sho,uld be modified sucb that the antenna position
will control the exposure rate .~o each exposure corresponds to a
360° azimuth sweep. The camera should be operated wheneyer radar
data are tape recorded.
111-43
The radar wi 11 be equipped wi th a VHF radio. It can be monitored
to obtain limited inforll3tion on the location of aircraft during
extensive case study missions. There is also an L-band IFF system
which will display aircraft locations. It does not have the capa­bility
to distinguish unique transponder codes and does not record
the aircraft location on tape. The system should provide some
information such that notes concerning the location of test cases
between the two radars can be recorded. Since there will not be
a license to allow the radar to transmit on the project VHF fre­quency.
and the receiving range will be limited. the extent to
which the downwind radar will remain aware of aircraft operations
is an unknown.
D. Rawinsonde Observations
Two WSSI rawinsonde crews will be available at the Miles City site
to obtain rawinsonde data for direct program support. These crews
wi II be available to prOVide rawinsonde and weather forecast sup­port
services during the period 0800 to 2130 on all operational days.
A minimum of one routine sounding per day will be taken on a 6-day­per-
week basis. A routine release will be made at 0830 MDT (1430 Z).
This first rawin will be primarily used in developing the 1200 fore­cast
and for modeling purposes.
111-49
Additionally. serial soundings will be taken on operational days
and. as decided by the project director. days when convective activ­ity
is forecast to occur. The main objective will be to obtain a
sounding inunediately prior to the onset of general convection, and
to continue releases on a routine basis throughout the entire con­vective
cloud development. and dissipat.ion period, or until the onset
of darkness. whichever occurs first. The launch time of t.he initial
serial sounding will be flexible, depending upon the 'forecast onset.
of convection or when cumulus begins. Aft.er the init.ial launch,
releases may cont.inue routinely at between 2- and 3-hour intervals,
at the project director's discretion.
In addition. an 0830 rawinsonde release will be made 6 days per week
from the downwind radar site at t.he Baker, Mont., airport per instruc­tions
from the project director at Miles City. A Weather Measure
Corporation RD-65 rawinsonde system incorporated in the radar van
will be used for data collection. It is anticipated that a hangar
space will be utilized for balloon inflation and supply storage.
This site will also be equipped with a t.ime-share computer terminal
for rawinsonde processing.
Rawinsonde receiving and recording equipment will be calibration
checked and adjusted (if necessary) to manufacturer specifications
III-50
prior to each release. At least weekly checks of the receiver antenna
orientation and level will be performed by contractor personnel and
noted in a log. These checks and all phases of the data collection
and reduction will be monitored throughout the field season on a
spot-check basis by DAWRM personnel.
All sOWldings ""ill be made in accordance with specifications contained
in the latest revision of Federal ~feteorological Handbook NO.3,
Radiosonde Observations. It will be attempted to track and record
all sondes to the IOO-mbar level if practical. In the event that a
sonde cannot be tracked and recorded to at least the 400-mbar level.
an additional sounding will be required, again attempting to reach
the IOO-mbar level.
Data collected from the routine morning sounding wi 11 be processed
inunediately and utilized for forecast purposes. All other soundings
will be processed in as near "real time" as practical. However.
obtaining serial release data will take precedence over data reduc­tion.
All soundings will be processed using facilities of the CYBER-74
time-share computer system. Time~share terminals will be located in
the Miles City rawinsonde trailer and Baker radar van for this pur­pose.
Both should call 232-5717 for computer access.
III-51
E.. Surface Measurements
PNeipitation
Approximately 160 recording rain gages of varying sophistication
will be utilized during the summer field season. The installation,
operation, and data handling associated with these gages will
require a team of professional meteorologists, technicians, and
data clerks. The total effort will require close coordination to
accODlplish the objectives of the precipitation measurement por­tion
of HIPLEX.
The Montana Department of Natural Resources and Conservation (DNRC)
will establish all rain gage sites in the primary network and
clusters. They will choose locations, arrange leases and permits,
and fence all sites as necessary. The DNRC will abo calibrate,
install, and operate all Belfort weighing rain gages.
All Belfort gages will use 24-hr chart drive gears (one rotation
per day) so that seven traces will result on the chart between
weekly servicing. The funnel. will be removed from the bottom end
of each gage's collector tube allowing water to evaporate" from
the -catch bucket between rainfall periods. The resulting slight
separation between daily traces during nonrainy periods will
III-52
greatly facilitate chart reading. To insure that water is ade­quate
for evaporation, at least 25 ram (l in) should always be
left in the bucket after servicing, as determined by the absolute
chart reading. It may be necessary to increase this to as much
as 50 mm (2 in) during the hottest portion of the swmner.
All gages will be precalibrated using Belfort standard weights
prior to installation in the field. Calibrations must be accurate
to within plus or minus 0.25 nun (0.01 in) over the full ISO-nun
(6-in) span for the unit to be declared acceptable for field instal­lation.
After the calibration is achieved, the gage mechanism will
be secured before it is transported. The gage calibration will be
rechecked and adjusted, if necessary, to provide the same accuracy
after it is installed at its field station. Subsequent recalibra­tions
will be performed at approximately the midpoint and at the
end of the data collection season.
All spring-wound and electrically driven gage clocks will be test
run for at least 2 weeks prior to field installation. This will
be accomplished at the Miles City headquarters. Necessary adjust­ments
will be made so that each unit perfoTDlS to an accuracy of
at least plus or minus S min per week prior to field installation.
Minor adjustments will be made when necessary during routine field
III-53
servicing to maintain this accuracy throughout the data collection
Each Belfort gage will be visited once per week for routine serv­icing.
During servicing the gage chart will be changed. The date~
time~ location~ instrument identification. water amount, and serv-icing
personnel's initials will be marked on the chart at both
time of installation and removal. A log form specifying pertinent
service information will be completed after each gage servicing.
Minor failures of manual gages will be repaired during routine
servicing. A field recheck of the repaired gage will, generally.
be made within 2 days after repair. Any gages which experience
major failures (for example~ vandalisJl), will be removed from the
field and re"turned "to the Miles City headquarters for repair.
Strip chart data obtained from the Belfort gages will be reduced
at the Miles City headquarters. They will be compiled into the
computer-compatible form to be specified by DA.WRM in Denver.
Manual network data reduction will commence upon receipt of indi­vidual
charts and continue throu~hout. and for some time- after. the
field season. Each chart will be spot checked by the data clerk
supervisor within 3 days of the chart change. A.ny problems will
immediately be reported to the DNRC supervisor. All charts will be
reduced at IS-minute intervals (starting on the hour) by noting
the chart reading to the nearest 0.2S mm (0.01 in). Unless a suit­able
chart reduction machine is available, this is most efficiently
done by two persons. One reads the absolute inches of water from
the chart trace while the other writes the information on an IBM
card punch form. A second independent reading should be made at
a later date. Both sets of readings are entered into the CYBER-74
computer system for comparison, and all discrepancies greater than
0.25 DIll (0.01 in) are then resolved by reference to the original
charts. These procedures are further discussed in Montana Technical
Report 76-1.
The installation, maintenance, and operation of the entire LANDSAT
and memory gage systems will be the responsibility of Western
Scientific Services, Inc. (WSSI). It is not practical to determine
what routine servicing schedule will be required for the LANDSAT
and memory gages until additional field experience is gained. Thus.
the details regarding maintenance needs will evolve during the field
season. However, whenever a LANDSAT or memory gage is discovered
to be malfunctioning, WSSI personnel will promptly repair the gage.
Data from the LANDSAT gages will be recorded on cassette tape at
the central station in the center of the LANDSAT portion of the
In-55
primary network. Data from the memory gages will also be recorded
on cassette tape on a receiving and recording systell carried aloft
by a light aircraft. Flights will be required on approximately an
every other day basis to prevent data loss because the memory capac­ity
of the gages is 256 IS-minute intervals.
All collected data will be promptly entered into the CYBER-74 com­puter
system for initial error analysis.
The amount of water in each wedge-type gage (to the nearest 0.25 llIII
(0.01 in) will be logged at each visit to any rain gage site. The
date, time, and observer will also be noted. The gage will then be
completely emptied by sharp downward shakes of the wrist. There­after,
a premeasured amount of light oil will be added. This will
reduce evaporation. Finally the gage will be returned to its holder.
Hail pads will be located at all Selfort and LANDSAT gage sites.
These will be inspected during each routine service visit. Those
units showing any indications of hail damage will be replaced with
a new pad, and the entire pad with damage (foil and styrofoam) will
be transported to the Miles C.ity headquarters. Care should be
taken to prevent further damage and denting to the pads during
transport.
III-56
Hail pads will consist of 25-mm (I-in) thick styrofoam square
blocks, 30S nun (12 in) on a side, which will be furnished by DAWRM.
The project director will be responsible for covering the styro­foam
with I-mil alUllinum foil (also furnished by DAWRM). which is
to be wrapped over the top and sides of the styrofoam blocks, and
stapled around the bottom of the block. The aluminum is to fit
over the styrofoam as snugly as practical. The completed hail pads
are to be placed on the ground after the ground surface has been
cleared of all grass and litter and leveled to a hard surface.
The pad is to be secured firmly to the ground by a large (about
ISO-nun-long) spike or nail driven through the middle of the pad.
No brush or other obstructions (including rain gages) should be
closer to the pad than twice the height of the obstruction. Grass
within 1 meter of the pad should be kept trimmed to below about
100~nun height. Also, the ground under each pad should be checked
periodically, and cleared of any growth, to prevent a "spongy"
surface under the pad.
Hail pads must be marked in the field with their location and "on"
date and time (at the time of initial exposure), and "off" date
and time (at the time of replacement). The observer's initials
should also be noted at both on and off times. These notes are to
be permanently placed on the bottom (non-fail-covered) side of the
pads with felt-tipped pen (dark blue or red color) which uses
waterproof ink.
III-57
To operate the precipitation gage networks during 1976 in a reason-able
and syst'ematic way, a task schedule is mandatory. as the inter-play
of manpower to operate all gages is significant. A detailed
task completion schedule follows:
January 30, 1976
February 13, 1976
February 16, 1976
March 5, 1976
March 19, 1976
March 22. 1976
March 29, 1976
Additional fencing materials are ordered.
Siting of 72 new rain gage plots begins.
Bench calibration of 41 Belfort rain gages
already at Miles City begins.
Transport of 50 Belfort rain gages from
Denver. Colorado. to the Miles City
headquarters.
Completion of new gage site selection.
Permission for their use is secured from
private landowners and is requested from
public agencies. Bench calibration of all
Belfort rain gages is completed.
All fencing materials are delivered. Fenc-ing
of new gage sites begins. Installation
of Belfort and ~edge-type rain gages begins.
West,~rn Scientific personnel arrive with
50 LANDSAT rain gages and 20 memory rain
gages. Installation of the LANDSAT rain
gages begins.
III-58
April 5, 1976
April 15, 1976
June 14. 1976
June 25, 1976
August 2, 1976
August 13, 1976
October IS. 1976
Field calibration of Belfort rain gages
in the field begins. Installation of the
memory rain gages hegins.
Fencing is completed. All rainfall net­works
aTe calibrated and fully operational.
Reduction of rainfall data begins.
Field recalibration of Belfort rain gages
begins.
Field recalibration of Belfort rain gages
is completed.
Field calibration check of all rain gages
begins. Removal of all rain gages begins.
Removal of all rain gages is completed.
Computer data reduction of all 1976 rain­fall
data is completed.
Cz,qwj Condensation and Ice Hue Z,8i
Cloud condensation nuclei Deasurements will be made once each oper-ational
day at 1500. I'iSSI radiosonde personnel will be trained
by J. McPartland in the operation of the Allee thermal diffusion
chamber to be utilized. A series of photographs will be taken
each day. The first will display an identification card showing
the location, date, and tille observations were started. The
III-59
relllaining pictures wi 11 record CCN concentrations at supersatura­tions
of 0.5, 0.8, and 1.1 percent. Three individual samples will
be obtained for each supersaturation. The droplet concentration
for each of the individual samples will be recorded on a sequence
of four pictures. The first exposure will be made at the instant
that droplets are first observed forming in the chamber. The
remaining frames will be taken at I-second intervals. This process
will allow maJ(imum concentrations to be determined in the data
reduction process. All exposed film wi 11 be conveyed to
J. McPartland at Miles City headquarters.
Ice nucleus measurements will be obtained using 0.45_pm membrane
filters contained in factory-loaded plastic field monitors. One
membrane will be exposed each operating day of the field season.
This sample will consist of air samples drawn through the membrane
for I minute out of each 5 minutes during the period 1200 to 2100.
These start and stop times will allow routine servicing to be
accomplished by WSSI radiosonde personnel while still yielding
a good sample of the typical daytime period of convective activi ty.
Equipment to be utilized will consist of two timers. a small vacuum
pump. and a flowmeter. The first timer will be used to establish
the daily operating period of 1200 to 2100. This unit will be
checked each operating day and if necessary. time corrected for
power outages. The second timer wi 11 be set to operate dte vacuum
pump for 1 mnute of each 5-minute time block during the daily
III-60
period. Complete operating instructions will be furnished with
the unit. Personnel servicing the equipment ....ill monitor its
function once each day and, if necessary, adjust the controllable
flowmeter to achieve a sample flow rate of 2.0 1m. A log of equip­ment
operation and servicing will be maintained. Exposed membranes
will be sealed, labeled with their place of origin and date of
exposure, and forwarded to Or. G. Langer at NCAR for processing by
his lab.
Time-lapse Super-8-1llDl films from the stereo pair of ground-based
cameras will be changed every fourth day, preferable during night
hOUTS or early morning. The month card will be changed when appro­priate
and the date corrected on the digital clock at the end of
April and June. The clocks will be checked for evidence of power
failures and reset if necessary. The I-minute timers are to
trigger the cameras on the minute as given by the WWV time signal.
Digital clocks are to be a half minute fast so that they will not
be changing their numbers during a photo.
The l6-mm time-lapse camera will be set in place at the rawinsonde
site during preparations for aircraft examinations of the clouds.
The crew at the site will be advised by phone from the radar of
the azimuth of the case study and will rotate the camera to that
1I1-61
azimuth. The azimuth of the cameTa should not be changed unless
a majoT correction is necessary. The timer and clock will be set
as above and a date card lIust be placed in view. The camera main­spring
must be fully wound before operation; it will then be good
for 10 hours. Film will be changed when necessary; many days of
operations can be recorded on one film.
Still photographs of clouds will be made at irregular intervals.
The frame number, time, date, location, and subject will be
recorded manually for each photo. At the end of the day (or begin­ning
of the next) the last photo should be of a display giving
the date and times of all photos taken that day.
F. Satellite Data Collection and Analysis
Satellite iIlagery will be received continuously 24 hours per day for
sectors appropriate to HIPLEX operational priori ties. The standard
observation sector will be the KB-4 i-mile sector. This will pro­vide
infrared imagery at night and visible imagery during the day
covering the entire High Plains. Special half-mile sector coverage
may be obtained from the SA-2 se~tor during intensive Miles City oper·
ations as required by the field site director. Each change of sector
coverage requires two telephone calls to the SFSS in Kansas City
(8.758-3749): (1) a call requesting the change from the standard
sector to the special sector; and (2) a call requesting the change
111-62
back to the standard sector. upon completion of special sector cov-erage.
These calls must be placed upon completion of transmission of
the current sector and before transmission of the special sector
begins. ooE5-1 illagery begins transmission at 12 and 42 minutes
after the hour, and SMS-2 imagery begins transmission at 27 and
57 minutes after the hour. Transmissions last 11 to 15 minutes.
Thus. when switching coverage between satellites, care must be taken
to receive the start signal so that data are not lost.
Routine analysis of satellite imagery for field operations should
include the following:
Analysis of location, rate of development, and movement for
all major convective cloud systems within sao kIl. of the field
site.
b. Notation of all meso/synoptic-scale organizations within
1.000 kilt of the field site. including downwind systeIlS.
c. Special notation of mesoscale triggering mechanisms including:
(I) Mesohigh arc lines
(2) Gravity waves
(3) Convergence lines
III-63
I .'~
I,~ . ~
(4) Areas of differential heating - fog/status. etc.
(5) Jet-lets
(6) Vorticity sheets
This information should be reported on standard forms shown in
appendix J.
In addition to the detailed satellite imagery observation log. a daily
summary log describing the important features of each day shall be
maintained. This will provide a quick look tabulation of important
meteorological features visible on the imagery. the sectors received.
and image quality, as shown on the Imagery Data Log (see appendix J).
Laserfax iJnagery should be mailed to DAWRM. Attn: Dave Matthews. at
the end of each week for further analysis. The attached form should
be used to log all important phenomena routinely as t.hey evolve.
Imagery should be archived chronologically with satellite logs for
ea~h day maintained in each day's file.
Digital Data Collection from White sands Missil-e Range (WSMR)
The project meteorologist. as required, will inform CSU personnel
at White Sands. telephone (8·898-1488 or 1489) of the scope of each
days' operation following the morning briefing. if applicable. When
special extended observations are required he shall so infot"lll these
111-64
personnel prior to 1100 MDT. If this inforlll8.tion is not provided,
digital satellite data will be collected for climatological and
case study analysis from 1600 GMf (1000 MDT) to 0000 GMT (1800 MDT).
G. Safety Considerations
Aircr>aft Operations
The regulations below are general in nature and it is expected that
each aircraft group associated with the HIPLEX program may wish to
adopt more stringent regulations. It will be the responsibility of
each aircraft command pilot to inform all personnel participating
in any way with the aircraft operations of additional safety rules.
(1) Ground Safety. - All ground operations, including instal­lation.
testing and maintenance of scientific equipment, aircraft
maintenance. loading. fueling, and aircraft movements will be
conducted by or under the direct supervision of appropriate
personnel supplied by the contractor.
No sm

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'HIPLEX
1976 OPERATIONS PLAN
MILES CITY, MONTANA
Site headquarters located
at Miles City Airport
1 mile north of Miles City
on Highway 11 (North 7th St)
Mailing Address
High Plains Cooperative Program (HIPLEX)
P.O. Box 1350
Miles Cily, MT 59301
Phone Number
(406) 131-5030
DEPARTMENT OF THE INTERIOR
Bureau of Reclamation
J
1. HIPLEX OVerview and Objectives............... 1-1
A. Introduction.......................... I-I
B. HIPLEX History........................ 1-2
C. Specific Objectives for 1976 1-6
D. Nonlleteorological Impact
Investigations ...............••••.•• 1-11
II. Observation Systems ..•.•.•.•.•...•....•...•.• II-I
A. Aircraft Observations ...•.••••••.•..•. II-I
CSI Cloud-top Aircraft .....•....••..... 11-4
MRI Cloudbase Aircraft •..•.••••.••...•. 11-8
Aerosol Aircraft ........•••....••..•••. 11-9
Survey and Seeding Aircraft............ 11-9
Aircraft Camera Systems ....•...••..•.•• 11-10
B. Radar Observations II-Il
CONTENTS - continued
C. Surface Precipitation Networks ....••.. II-IS
Primary Rain Gage Network ....•••...•... II-17
Rain Gage Clusters II-18
LANDSAT Rain Gage System............... II-19
Memory Rain Gage System................ II-20
D. Rawinsonde Observations .......•.••.••• II-21
E. Ground-based Cloud Condensation
and Ice Nucleus Measurements •.....•. II-22
F. Ground-based Phot9sraphy ..........•.•• I1-23
G. Satellite Data........................ 11-25
H. Weather Data Systems for
Forecasting......................... 11-26
III. Operational Considerations and Procedures .... III-l
A. Daily Field Opera-dons................ III-l
General Scheduling..................... IIT-l
Daily Schedule of Operations •..•.•.••.. ITT-3
ii
CONTENTS - continued
Debriefing Sessions .........•••••...••.
Daily Briefing Sessions- ••..........•. ; ..
Forecasts ...••............•........••..
Baker, Montana, Downwind Site ......•...
Airspace Coordination ........•.••..•...
Suspension Criteria •......•.......•....
B. Aircraft Utilization •.. ; •.•.•........•
CSI Cloud Physics Aircraft ••..........•
MR.I Cloud Physics Aircraft ..•....•.....
Aerosol Aircraft .................•..•..
Survey and Seeding Aircraft •.....•...•.
Decisions ........•...............•.•.•.
Calibration .......••..••...••.•.••.....
C. Radar Utilization· .....•...•....•....•.
Miles City Radar .
Baker Radar ...........•........•.......
iii
111-3
111-6
1II-7
III-8
III-9.
III-lO
111-14
III-24
III-25
III-27
111-29
III-31
III-33
III-36
III-36
III-45
CONTENTS - continued
D. Rawinsonde Observations ...•.•.•.......
E. Surface Measurements •...•..•......•...
Precipitation .......•.....•.••.........
Cloud Condensation and Ice Nuclei .
Photography ...........••..•.•.•.......•
111-49
III-52
III-52
III-59
III-61
F. Satellite Data Collection and
Analysis ......•••...•.••••..•...•..• 111-62
Digital Data Collection from
Nhite Sands Missile Range (KSMR)
G. Safety Considerations ....•...•....•...
Aircraft Operations .
Persons Allowed on HIPLEX Flights .....•
Radar Operations .
General Field Operations •......•.......
Fire ..•••.•........•...•............•..
iv
111-64
111-65
111-65
111-66
111-68
111-68
111-72
c
CONTENTS - continued
IV. Data Management............................... IV-l
A. Aircraft •.. ~.......................... IV-l
B. Radar................................. IV-2
C. Precipitation Networks................ IV-6
Belfort Rain Gage Data................. IV-6
LANDSAT Rain Gage Data................. IVw7
Memory Rain Gage Data.................. IV-8
Wedge-type Rain Gage Data.............. IV-8
Hail Pad Data •... ,...................... IV-9
D. Rawinsonde............................ IV-9
E. Cloud Condensation and
Ice Nuclei •.•••.•••••..••••..••••••• IV-II
F. Surface Photography................... IV-II
G. Satellite Data........................ IV-12
V. Support Facilities •••....•....•..•.•....•.•.. V-I
CONTENI'S • continued
A. Transportation........................ V~l
Federal Motor"Vehicles •..•...•••..•.•.. V-I
State Motor Vehicles V-I
Private Contractors.................... Y·2
COIMlercial Transportation Services •.... V-2
B. COIIJIlUnications and Cosputer
Time-share Systea •.••....•••.••..••• V-3
Telephone Communications ••..•..•••••••• Y-3
Radio CollllllUtlications •......•....•.••••. V-4
Computer Time-share System............. V~4
c. Shop Facilities •..••..••.•.•...••...•• V-5
APPENDIX~S
Appendix A SlfR-75 Radar Operating Capabilities A-l
Appendix B Radar Operato.r 1s Checklists ......•..•.•...• 8·1
vi
APPENDIXES - continued
Appendix C FOnlat for Radar Magnetic Tape Labels C-l
Appendix D Electronic and Sphere Calibration
Procedures: Miles City and
Baker Radars '............................. D-l
Appendix E Aircraft Calibration Experimentation
at Miles City ......•.............•...••.. E-1
, j
Appendix F Miles City HIPLEX Field Operations
Participants and Organizations •.....•...• F-l
Appendix G Sunset and Evening ~ivil Twilight
Times for Miles City. torr (~IDT) •....••...• G-l
Appendix H Local Advisory Committee................... H-1
Appendix J Satellite Sector Descriptions and
Data Logs ..•..•••..••••••••••••.•.•..••..•. J-1
vii
TABLES
1. Measured parameters of
HIPLEX aircraft systems
2. Skywater C-band radar (SWR-75)
general systca specifications
3. Daily operations schedule .•.•••••.••.•••••....
4. Data outputs expected on pap.er by 1030
on the day following cach flight ••.•.•••••..
1I-3
11-13
I1I-4
5. Rainfall rate vcrs.us dBz
for SWR-75 at a 42-km range................. A-21
6. Satellite observation log' code................ J-8
viii
FIGURES
1. Map of Miles City experimental area
and facilities.............................. 1-3
2. Standard flight patterns for
cloud penetrations.......................... 111-21
3. Aircraft positions during
missions for CSI. MRI. aerosol (A).
and survey/seeder (ss) aircraft .......•••••• 111-23
4.
s.
6.
7.
SWR-75 operators notebook ......•.•...•...•....
Magnetic tape data format ........••..•...•....
VSWR versus power values ....•........••..•....
HIPLEX organization chart , .....•.•...•...•••••
111-46
A-22
0-32
F-6
8. Satellite observation sectors
(4 sheets) .••.•.•••.•••........•...•........ J-3
ix
FIGURES - continued
9. HIPLEX satellite obs.~at1on 10; •...•••••••••• J·7
10. LASERPAX data 101 ••••••••••••••••••••••••••••• J·12
HIPLEX 1976 OPERATIONS PLAN
FOR
MILES CITY, OONTANA
1. HIPLEX Overview and Objectives
A. Introduction
The lIigh Plains Cooperative Program DUPLEX) is part of the Bureau
of Reclamation's Project Skywater. Project Skywater has the overall
goal of developing an effective weather modification technology, sci­entifically
and socially acceptable. for precipitation management to
serve a portion of the Nation's \~ater resources needs.
The overall objective of IIlPLEX i~ to develop this technology for the
High Plains. The il:nnediate objective is to attain operational capa­bility
with showery. wal'1ll-season cumulus precipitation, with the pros­pect
that investigation of precipitation from cyclonic and upslope
cloud systems will follow.
Three experimental areas have been chosen for HIPLEX. These surround
Mi les City. Mont., Colby-Goodland, Kan., and Big Spring-Snyder, Tex .•
representing, respectively, the northern. central, and southern High
Plains. Three sites were chosen because climatic conditions and cloud
I-I
characteristics vary significantly over the north-south extent of the
High Plains. It is Wllikely that each portion of the overall HIPLEX
field research will receive equal ecphasis at each site. Certain
activities can be concentrated at a single she with good assurance
that the understanding gained will be reasonably applicable to the
entire High Plains (for example. field calibradon of seeding sys-tems).
Other types of activites. such as examination of cloud micro-physical
processes, may require work at each site because of known or
suspected north-south gradients in cloud and climatic properties.
This document concerns field operations to be conducted in the Mi les
City area during the 1976 SUllU1ler field season. which will extend from
April 22 through July 31. Figure 1 shows the general project area
and location of facilities.
B. HIPLEX History
After the Bureau of Reclamation was assigned as lead agency for IHPLEX.
a preliminary scientific plan. the HIPLEX Technical Plan. was prepared
by the Bureau's Division of Atmospheric Wat.er Resources·Management
(DAWRlot). The plan was distributed to many scientists and interested
individuals and organizations du;ing early 1974. A workshop (held at
Vail. Colo., July 22-25, 1974) used the preliminary Technical Plan as
a useful "stepping stone" in pursuing the development of an opdrnum
1-2
fi.ap of Miles City. Montana
E:qler1Jnental Area and Facilities
Figure 1. - Map of Miles City experimental area and facilities.
1-3
:.j'.
o
scientific approach for BIPLEX. The many valuable discussions held
at this workshop, together with the considerable correspondence that
followed, have been fully considered by DAl'iRM.
Another noteworthy workshop was held at Colorado State University,
October 10-12, 1974. The primary topic of this workshop was the
design of the Colby-Goodland, Kan., portion of IlIPLEX. However, most
of the discussion was general in nature and applicable to all HIPLEX
sites.
The first BIPLEX field activity took place at Miles City during mid­July
to mid-August, 1974. A limited program of radar and' ground-based
photographic observations was carried out. Data obtained were useful
in planning the Montana field activities for the 1975 season.
Field operations were conducted at the three HIPLEX sites during the
1975 sununer. In large measure, this field season was devoted to the
installation, testing, and general "shakedown" of a wide .variety of
experimental equipment and procedures. In addition, complete field
facilities had to be established in Kansas and Montana before and
during the field season. As equ,ip1l}ent was brought "online," data
collection commenced. A considerable 'amount of precipitation, rawin­sonde,
and radar data were 'acquired at- each site. -In addition, survey
flights were .successfully completed at all sites; these established
1-4
the detailed characteristics of the background aerosol. Also, at
least a limited amount of sampling of cloud microphysical and dynamic
processes was carried out at each experimental site.
The first of a series of HIPLEX Technical Conferences involving the
entire HIPLEX "family," representing all contractor £inns and agen­cies,
and DA1'm,M staff, was held in Denver on June 16-20, 1975. During
that conference, special panels met to make recommendations concerning
five aspects of HIPLEX bearing on analysis: (1) precipitation meas­urement,
(2) synoptic/mesoscale studies, (3) cloud/subcloud studies,
(4) intensive case studies, and (5) value analysis. Participants rec­ommended
additional HIPLEX technical conferences before and after each
operating season. The second such workshop was also held in Denver
on December 16-18, 1975. At this time several written reports were
presented describing the preliminary results of the 1975 field sea­son's
activity. Additional workshops are planned at several month
intervals. These conferences are proving invaluable for program
planning and coordination.
Discussions developed at the workshops, concerning HIPLEX design,
have continued at DAWRM, reSUlting in many of the ideas being incor­porated
into the plans. The experimental design for HIPLEX, being
cooperatively developed by the staffs of DAWRM and the Illinois State
l'later Survey, is of an evolving nature. As knowledge increases, it
1-5
will be used to modify and upgrade the experiment to optimize the
learning efficiency of HIPLEX. The present concept is that HlPLEX
will be a three-phase experiment. The first phase is of an explor­atory
nature leading to a better tmderstanding of natural precip­itation
processes and the design of a quasi-isolated cloud seeding
experiment. The activites of the 1976 season will be part of the
first phase. The second phase will be the actual conduct of the quasi­isolated
cloud seeding experiment which, if successful, will lead to
the design of a wide-area cloud seeding experiment. The third and
final phase would be a wide-area experiment attempting to increase
the net rainfall over several thousand square kilor.leters.
C. Specific Objectives for 1976
It has been decided that an improved physical understanding of natural
cloud and precipitation mechanisms in the northern High Plains should
precede a final design for testing seeding hypotheses. The existing
evidence is not sufficiently clear. on several critical points. More­over,
certain experimental procedures concerning the actual seeding of
clouds and the measurement of precipitation require explanation. Among
the more important questions that should be answered more fully are:
(1) What -is the role of naturally fonned ice crystals in the area's
rainfall regimes? At what· temperature levels· and in what.l.concen­trations
,do they:: occur? \'Ihat is the role of riming?
1-6
(2) What is the natural cloud droplet concentration and size
spectra as a function of cloud life cycle for important cloud
regimes? Is the coalescence mechanism important and does hygro­scopic
seeding appear to have potential?
(3) What is the climatology of clouds by type, size, and fre­quency?
\'ihat is the associated atmospheric structure as revealed
by rawinsondes? How are rainfall amount, frequency, and mechanism
related to cloud types?
(4) What delivery methodes) for cloud seeding agents are most
effective for various storm types? How rapidly do the seeding
agents diffuse through the cloud systems? What concentrations of
ice crystals actually resul t in the cloud from introduction of a
given type and amount of ice nuclei?
(5) What is the most practical and reliable method of measuring
rainfall (a) from quasi-isolated convective clouds, and (b) over
an area of several thousand square kilometers? Does seeding lead
to significant changes in the drop-size distribution and, hence,
the Z-R relationship? How important is evaporation below the radar
beam? \'ihat rain-gage density is sufficient for evaluation of a
quasi-isolated cloud seeding experiment? Is a combination of radar
and gages the best approach and, if so, what is the optimum combi­nation
configuration?
1-7
The operations plan for the 1976 field season is intended to expand
the preliminary efforts of the 1975 season in further solving these
and other similar important questions for the Miles City region. It
would be optimistic to believe that these questions could be answered
fully during the 1976 field season. However, it is believed that a
substantially improved state of knowledge will reSUlt, which will
guide further research efforts.
In order to improve understanding of natural cloud processes and cer­tain
aspects of weather modification technOlOgy, several specific
objectives have been established for the 1976 field season in Hontana.
These objectives, along with some specific approaches to meeting the
objectives, are listed below.
(1) Obtain the necessary data to evaluate whether radar alone,
rain gages alone, or some combination of the two systems provides
the most practical and reliable oethod of obtaining rainfall meas­urements
for evaluation of cloud seeding. This will be partially
accomplished by operating a primary network of 109 rain gages (plus
6 cluster networks of 3 gages each) in combination with two 5-cm
digitized radars monitoring the convective storms from opposite
sides. Additional measurements· pertinent to this problem will
include airborne and ground disdrometer measurements of the vari­ation
of Z-R relationships with time and space. Airborne dis­drometer
data will also be obtained above the rain gages while
1-8
within the radar beam. AUempts will be made to estimate evap­oration
between cloudbase and the ground. The two radars will
monitor convective stOI'lllS from opposite sides to help estimate
attenuation. The need for providing windshields for rain gages
will be evaluated from field data. Hail pads at all gage sites
will help clarify the potential problem of marked changes in the
Z-R relationship due to the presence of hail.
(2) Obtain detailed data from cloud physics aircraft. radar, rawin­sonde,
and possibly rain gages which will permit in-depth case
study analysis of several convective cloud systeJ:ls. Such infor­mation
is vital to an improved tmderstanding of convective cloud
precipitation processes. Numerical model testing and development
will be utilized extensively in this regard.
(3) Collect information concerning the mean frequency distributions
of several important cloud properties which bear on the potential
for weather modification. Examples include ice-nuclei and ice­crystal
concentrations as a function of temperature and time, cloud
condensation nuclei as a function of supersaturation, cloud droplet
spectra, sizes and magnitudes of cloud updrafts, cloud diameters,
heights and temperatures of both c10udbase and top as a function
of the cloud life cycle, and first echo heights and temperatures.
Survey flights will be routinely made by a light aircraft with
1-9
limited instrumentation to docwnent some of these properties.
Others will be determined by radar. by ground- and aircraft-based
time-lapse cameras, or by cloud physics aircraft during intensive
sampling of convective clouds. Rawinsonde data will be combined
with data from the other measurement systems to estimate certain
properties (for example. cloud-top temperatures).
(4) Investigate the dispersion of seeding material within clouds
for three modes of seeding (cloudbase, at the minus S° C level,
and from cloud top). Also, attempt to document ice crystal devel­opment
caused by seeding. This general area of research is referred
to as "calibration seeding" and is intended to test the three seed­ing
modes under actual field conditions. The question to be exam-ined
is: To what extent does silver iodide seeding of a particular
mode, with a known type and amount of material, modify the ice crys­tal
development and growth within small- to moderate-size convective
clouds? Al though cloud seeding has be~n conducted for the last
three decades, documentation of seeding-induced microphysical changes
within clouds is still quite limited. The calibration seeding
to be conducted during 1976 will build on the recent work by NCAR.
Instruments aboard a sailplane were used to detect both the seeding
material (as ice nuclei) and ice crystal concentrations. In the
planned HIPLEX work, powered aircraft will repeatedly.penetrate
a seeded cloud to 'monitor ice nuclei and ice crystal ·concentrations.
1-10
(5) Develop objective forecasting techniques for the formation of
convective clouds, and an estimate of their natural precipitation
potential including probable area and mean amount. Forecasting
will, of course, be quite useful in planning each day's activity.
Even more important, objective forecasting could be very helpful
in the design and conduct of future weather modification exper­imentation
us it may provide a basis for prepartitioning of the
data. This could lead to much more sensitive statistical testing
of seeding effectiveness.
D. Nonmeteorological Impact Investigations
I'/hile this operations plan covers only the meteorological portion of
Miles City llIPLEX, other important aspects should also be noted. The
Montana Department of Natural Resources and Conservation is directing
a research program concerned with the agricultural, economic, environ­mental,
hydrologic, and social aspects of potential swnmer rainfall
modification. Thus, if llIPLEX succeeds in demonstrating area-wide
rainfall changes, the significant consequences of such changes should
also be tmderstood.
1-11
'- .. ' .' ~
"' , ~';:r. _-....- .
. .•• ~J ";'" •
. .' ... t ~~_l' :., ... ;.:..:
II. Observation System
A. Aircraft Observations
One of the primary goals of 1976 will be to develop an improved
understanding of the natural precipitation mechanisms in the Miles
City area. This should indicate some of the potential for cloud
IllOdification for the purpose of increasing rainfall at the ground.
Remote observations by radar. rain gages, and photography cannot
give details of the microphysical processes that fortll the rain.
Rather, direct, in-cloud observations as obtained by instrumented
ai rcraft. are needed.
Another primary goal for 1976 is to establish the spatial and tem­poral
variability of Z-R relationships for precipitating clouds in
the Miles City area. This will aid in evaluation of radar as a rain­fall
measuring tool for future seeding experiments. The aircraft are
needed to measure rainfall rates in volumes eXaJIlined by the radar and
to document the precipitation mechanism that is involved on an indi­vidual
case basis.
Three instrumented cloud physics aircraft will be utilized during
1976. The cloud physics aircraft intended for use primarily above
cloudbase is an Aero COmJll8J\der 680 FL operated by Convergence Sys­tems,
Inc. (CSt) of Ft. Collins, Colo. A second cloud physics air­craft.
nomally flOto'Jl. near cloudbase. will be a Piper Navajo, operated
II-I
by Meteorology Research, Inc. (MRI). In addition, an aircraft to
measure aerosols will be provided for the limited time of mid-JWle
to mid-July. 'nl.is aircraft. a 8-23 provided by the -University of
Washington, will also be utilized on some cloud physics missions.
A fourth aircraft. a Piper Aztec operated by Colorado International
Corporation. will be a combination cloud survey and seeding plane.
The survey missions will measure updraft profiles and tellperatures
at a large sample of cloudbases. It will also measure the moisture
. distribution in the subcloud layer.
The 1DOst important measurements for the microphysics studies
involve measurement of (1) the ice phase. (2) the liquid phase.
(3) the dynamical history. and (4) the nuclei of the cloud. Our
cloud seeding theories involve the introduction of appropriate
nuclei to increase the concentration of ice crystals at some tea­perature,
....hich then grow at the expense of supercooled ....ater. or
to increase the concentration of large droplets .....hich llay then
collide with and collect the Slll8ller cloud droplets. Questions
....hich should be answered before testing seeding hypothese are:
(1) are there adequate ice crystal or large water drop concentra­tions
(or nuclei to produce them) already present naturally; (2) is
there sufficient supercooled water from which the ice can grow; and
(3) is the cloud-droplet spectl'Ull broad enough to allow collision
and coalescence to proceed to produce precipitation drops?
The instrumentation on all aircraft is listed in table 1.
II-2
(
Table 1. - MQaswoed parameters of RIPLEX aircraft systems
Aircraft mission Cloud
f.leasurement Source Cloud Cloud Aerosol Survey
top base
time T T T
al titude-pressure T T T
-radar
airspeed T T T
heading T T V
position-VOR/DME T T V
-VLF T
rate of climb Ball T
angle of attack T
pitch T
roll T
accelerometer T
manifold pressure T
engine rpm
air temperature T T
dew point temperature T T
turbulence MRI T
liquid~water' content JI< T
NOM
drop spectra Pf.IS-ASSP
PMS-cloud
PMS-precip
ice concentration Turner-Radke T
foil impactor MRI P+T
bulk water
decel!erator-impactor (ice)
ice nuclei filters
f.lee 140
NCAR T
aitken nuclei T
nuclei spectrometers Royco T
CCN Mee 130 T
electric field T
events V+T V+T
photos-forward p
-side
-radar
voice recorder
computer tape recorder
(record type: T '" computer tape. P '" physical record. V '" voice tape or notes.
X '" not yet determined)
11-3
CBI Ctoud Top Ail'craft
The CSI cloud physics aircraft (Aero Commander 680 FL) has
instruments to record the location. altitude. and performance
of the aircraft. the standard dry-air properties. turbulence,
ice nuclei. and cloud particle (liquid and solid) properties.
Table I gives a list of these instruments. Much of the data
will be recorded on magnetic tape; other records will be foil,
ice crystals preserved in cold hexane and later photographed,
'and other photographs.
Several of the microphysical instruments will give comparable
data. Intercomparisons between such instruments provide a
partial check on the validity of resulting measurements. Also.
a degree of instrument redundancy is useful in cases of fail­ure
of a particular system.
The phenomena under investigation are discussed in the follow­ing
subsections.
The Ice Phase. - The ice phase of the cloud can be described
by the crystal concentration, sizes, and shapes. The CSI
cloud physics aircraft will have instrumentation (with some
redundancy) to determine these parameters.
II-4
(
c
The ice crystal concentration will come mainly from the
modified Turner-Radke laser-crossed polaroid electronic
counter with readout on magnetic tape. The instrument
counts only ice particles and not water droplets. Ice crys­tals
aggregated into flakes-would probably receive only one
count per flake.
Backup or cross-reference i~struments for crystal concentra­tion
will be the Particle Measuring Systems (PMS) large par­ticle
spectrometer (under the assumption we are looking at
ice only), the foil impactor, and the decellerator single­slide
ice crystal sampler using cold hexane. The spectrom­eter
provides electronic counts recoded on magnetic tape.
The foil impactor and hexane samples of ice crystals require
laborious visual analysis.
The crystal size can be determined electronically by the PMS
large particle spectrometer tmder the assumption that there
are no large water drops. Size information can also come
from the decellerator-sampler after visual examination.
Some crude size information may be available on the foil
impactor.
11-5
The crys'tal shape is obtainable only from the decellerator­sampler
after visual examination.
Ice crystal presence can be indicated inside clouds by inter­ference
with radio communication and sometimes by optical
indicators such as haloes.
The Water Phase. - The water phase can be described by a size­concentration
spectrum. This spectrum may be integrated to
provide a liquid-water content. a rainfall rate. and a radar
reflectivity. An air-temperature measurement will indicate
its degree of supercooling. Riming on surfaces viewed by
cameras crudely indicates amounts of supercooled wat,er.
The size-concentration spec.trum will be measured optically
by three PMS spectrometers. The ele.ctronic signals will be
recorded on magnetic tape. Two spectrometers size by. means
of optical arrays of photodiodes; the other measures by
optical scattering. The foil impactor. provides a b.~ckup
device for large drops. 'The decellerator-sampler m.ay also
give some infonnation.
The. liquid-wa.ter c,on-tent will be meas-ured, direct I}:'· b.y two
different hot-wire. deJdces (Johnson-Williams and a N.ational
It-6
Hurricane Research Laboratory prototype) and can be compared
to the calculations derived from the spectrum measurements.
The Dynamical History. - Most of the dynamical history infor­mation
will be gathered by the· photographic and radar systems
to be described. TI\is provides cloud exterior dimensions as
a function of time (and thus age of various portions of the
cloud).
Updraft information can come from the rate-of-climb instru­ment
accelerometer. altimeter. and air speed indicator if
the aircraft power settings are constant.
Turbulence probes will give diffusion and convection.
~. - Ice nuclei will be measured by a rotating
membrane filter device. and by a NCAR acoustical counter
operated at a constant reference temperature of minus 200 c.
No measurements of cloud condensation nuclei from the C51
aircraft are currently planned. Relevant infonation can be
obtained from the srnall droplet spectror.:leter if the aircraft
is operated just above cloudbase. The direct measurement
II-7
should be better than calculations from a nucleus spectrum
obtained from a counter operated at only one supersaturation
value.
MRI ctoudbase Aircraft
The MRI cloud physics aircraft (Piper Navajo) has instruments
to record location, altitude. and performance of the aircraft,
the standard dry air properties. turbulence. CCN. and liquid
cloud particle properties. Table I gives a list of these
instruments. Much of the data will be recorded on magnetic
tape; other records will be foil, photographs. and bulk water
samples. No ice-phase measurements are normally made by this
instrumentation. though the large PfolS probe could be used
WIder the assumption of no large water drops, and the foB
impactor could detect graupel and iC'e, crystals ~
The water-phase measurements involving" the PMS probes are the
same as for the C51 aircraft. No liquid-water content devices
are used on the,t-ffir aircraft. Instead~\ the ' PMS 'output is
integrated to provide this value. Bulk '" '-W'''
A (when available)
to radar -E--
raIn gage network
(a) Z-R studies (S8 idle or elsewhere)
-pho1:0a...{:>S8
::;~;~l 4-+------+--t>CSI 1_100 "ff --!O~O
j J ,~- ..x:==~.....,..,-j_ -- -»--E--- »"
0{ ~MRI ~A
~ 21
A (b) cumul1form life cycle study
Figure 3. - Aircraft positions during missions for CSI, MRI, A-aerosol, and
ss-survey-seeder aircraft
CSI Cloud Physics Aircraft
Z-R and Cwnulifol'trl Ute Cycle Study fMi.Bsion types A and B)
The aircraft is to climb to the minus 10·C level, located at
approximately 6 km*, allowing about 40 minutes for the climb.
The ascent should pass through as many clouds as possible to
provide extra lift and to provide extra random cloud samples.
The flight path should be in the direction of the expected
working area, and in formation with other instrumented air-craft
for as long as practical. The 40 minutes is sufficient
time to get to any location within the lSO-km radar range.
Once at altitude, the mission coordinator on board the C51 aircraft,
in consultation with personnel at the radar, will select a suitable
test case. Attempts will be made to select growing turrets as they
approach the minus 10·C level. After the turret passes about 300 111
above the aircraft, it will begin to penetrate the cloud, and will
repeatedly penetrate the same systell for the life cycle of the cloud
or until safety c~nsiderations or the aircraft scientist recOllllllend mov-ing
to a different cloud. Penetration directions should alternate
• All elevations in this plan are referenced to lIean sea level (asl)
unless otherwise noted.
111-24
(
between parallel and perpendicular to the shear vector, approxi­mately
according to the figure-eight pattern in figure 2a, until
the airspace becomes too cluttered with nearby and especiallY
unsafe clouds. The pattern of figure 2b may then be used. The
aircraft should maintain as 'lIIJch as possible an attitude for
level flight in still air so that updraft measurel:l.ents may be
most reliable. Altitude adjustments back to the minus 10°C level
are to be made after penetrations.
This flight procedure is the same for both natural and seeded
clouds. If clouds do not reach the minus 10°C level, a lower
flight level will be assigned. The aircraft will return to base
when directed by the mission coordinator or dictated by the fuel
supply.
MRI Cloud Physics Aircraft
Z-R Study (Mission type A)
The aircraft will depart with the CSI aircraft and proceed
towards the rain gage network, staying in formation for as
long as practical. The MRI aircraft will then descend to
sample rain in the radar beam tilted 1 degree above horizontal.
A map of the elevations of the beam over the network will be
provided upon arrival at the site. The aircraft track will
preferably be along VOR radial 041 0 over a line of gages marked
with fluorescent orange panels or along the VOR radial passing
over the Illinois State Water Survey (151'1'5) ground disdrometers.
If the rain is falling only over other gages, the track will
be through the rain in a radial direction. In general, the
aircraft will climb as it flies away from the radar and descend
as it returns to stay near the center of the radar beam.
CumuUfonn Life Cycle study (Mi88ion type B)
The aircraft will depart with the CSI aircraft. flying in the
direction of expected operation and clillbing to cloudbase.
The climb may take as long as 15 Jrinutesj total travel time
to the area of interest may be as long as 30 minutes.
After selection of a test cloud by the mission coordinator.
the MRI aircraft is to first fly about 300 m above c10udbase
in the updraft. making two perpendicular passes according to
111-26
(
(
the figure-eight pattern in figure 2a. It is then to descend
to between 100 and 300 m below cloudbase in the updraft and
continue to make figure-eight passes. Once rain begins to fall
from the cloud, the aircraft is to sample the rainshaft in the
figure-eight pattern until either the rainfall ends or the
mission coordinator recommends moving to another cloud. If the
cloud is raining upon arrival, the updraft passes below cloud­base
are to be omitted. However. the penetrations about 300 m
above cloudbase will still be made. These updrafts may be
sampled as a byproduct during the necessary aircraft maneuver­ing
outside of the rainshaft. Flight patterns are the same
for both natural and seeded clouds.
Aerosol Aircraft
The aerosol aircraft will generally make a daily vertical sample
of aerosols up to at least 5 km (usually above the haze layer)
during the afternoon. It will operate up to 7.5 km when employed
for cloud penetration work, both with seeded and non-seeded clouds.
This aircraft may also be used to substitute for either the "lRI or
111-27
CSI cloud physics aircraft if they are ever unable to operate for
any particular mission.
Z-R and eumuU.fom Life Cyete Study (Mission types A and B)
The aerosol aircraft will sample aerosols in the general vicinity
of the case study cloud. At ranges greater than 15 kill from the
case study cloud the aerosol aircraft may penetrate other cloud-bases.
However, whenever the aerosol aircraft is wi thin 15 km
of a case study cloud, it will maintain at least 1,000·m vertical
separation frOlll d\e case study eloudbase unless it has visual
contact with d\e MRI aircraft. In this case it Dlay operate up (
to 300 III below the MIt! aircraft. In some cases, expecially for
seeded clouds, the aerosol aircraft may be requested to pene-trate
the rain shaft below cloudbase or the cloud above the C5I
aircraft at about the _15° to _20°C levels. In such cases the
aerosol and MRI aircraft pilots, or the aerosol and CSI pilots.
will coordinate their rain shaft and/or cloud penetrations such
that either a vertical separation of 1.000 III is maintained or
only one of the aircraft is in the rain shaft and/or cloud at
any time.
(
III-28
When rainfall is occurring over the rain gage network, MRI
is to fly in ~he one degree tilt radar beam. for a Z-R study.
This may be transformed into an evaporation study as well by
having the aerosol aircraft fly above MRI at c1oudbase. The
rain will then be sampled at cloudbase, in the 10 beam approxi-mately
half way between cloudbase and the ground. and at the
surface.
Survey and Seeding Aircraft
Survey Missions
The survey aircraft will fly a prescribed flight pattern. such as
the hexagonal pattern illustrated in figure 2c, over known land­marks,
departing from such a route to fly under nearby clouds.
It will fly under the cloudbases, maintaining an aircraft attitude
and performance appropriate for level flight in still air. It
will fly one figut:'e-eight pattern, or a single straight pass if
the figure eight is impractical, under each c10udbase that is
sampled. When between clouds, the time, position, and elevation
will be recorded with a frequency that will penlit reconstruction
of the flight pattern such that the time and location of changes
in the continuously recorded temperature and dew point values can
be noted. In consultation with the aircraft coordinator (MRI
pilot). this aircraft will normally maintain a hori zontal separa­tion
of at least 15 km from intensive case study clouds, unless
involved in seeding such clouds.
Seeding Missions
Z-R and eunruUform Life Cycle Study (Mission types A and B)
The seeding aircraft will drop dry ice, burn or eject flares.
or operate acetone generators, as directed by the mission
coordinator. This seeding will occur (1) at or just below
cloudbase (after MRI has withdrawn fr01ll that airspace and is
in clear air). (2) at the O· to minus S·C level (while CSI is
in clear air), ·or (3) from a level above or near cloud top
(while CSI is in clear air). Burn-in-place flares or acetone
111-30
generators will be used at levels (1) and (2). droppable flares
will be ejected at level (3). and dry ice lIay be dropped at
levels (2) and (3). After seeding is accomplished, the seeding
aircraft will withdraw froll the cloud. It raay be directed to
maintain a position a few to several kilometers away froll the
seeded cloud while the crew takes still photos of the cloud and
carefully records the times of the photos and 3-D positions of
the aircraft. In general, somewhat heavier seeding may be con­ducted
during the early months until confidence is achieved in
detecting the resuaing ice nuclei and ice crystals. Seeding
rates may then be reduced.
Decisions
The mission decisiorunaking process will typically follow the follow­ing
sequence: Once suitable clouds for sampling are believed to be
developing, the mission coordinator will request that the aircraft
depart. The miss.i,on coordinator will fly in the CSI aircraft. Once
airborne. the mission coordinator. in consultation with scientists at
the radar, will select a portion of the experimental area for the
III-31
initial investigations. Aircraft operations will generally be con­fined
to a ISO-loa radius of the Miles City radar. Once at the
region of interest. the Ilission coordinator will select a particular
case study cloud from visual observation, and will report its posi­tion
'to the CS1 pilot, who will relay the position of the cloud to
the other aircraft pilots. with help from the aircraft controller.
The mission coordinator. in consultation with the scientist on
board the other aircraft, will decide when to cease sampling the
cloud and to proceed to the next cloud or return to base. Any
particular type of aircraft operation (for example, cloud pene­tration)
will be terminated by the pilot in cOlllll8nd whenever, in
his opinion. carrying out that operation would be huardous. The
project director will be notified of such tenaination, but it is
not necessary that the pilot discuss the situation prior to termi­nating
the operation. The pilot is in the best position to aake
such decisions and has the authority and responsibility to take
whatever action is necessary to insure the safety of his crew and
aircraft.
II1-32
(
The pilot of the MRI aircraft will coordinate each aircraft's
position by radio conversation with the other pilots and Salt
Lake City Air Route Traffic Control Center to insure safe separa­tion
is always maintained among all aircraft.
Calibration
During the start of every mission each aircraft will pass directly
over the radar prior to departing to its area of operations. The
cloud physics and aerosol aircraft will record their position on
their data systems. while the cloud survey aircraft will note the
DME and VOR readings on paper or voice tape. The time of visual
passage over the radar must be noted to the nearest second by all
aircraft with other than manual recording systems.
Every day as any aircraft is returning to base. it will be required
to fly visually over one known landmark. A list of landmarks to
be used will be provided to each pilot upon arrival at the HIPLEX
site. The list may be supplemented by photographs. One pass over
lII-33
the landmark is to be at constant distance from the VOR. while
another pass is to be made flying over the landmark radially towards
the VOR. Hand notes are to be made identifying which landmark it
was, and passover times are to be noted accurately. The cloud
survey aircraft will make hand or voice notes of the VOR and DME
readings each time it is just above the landmark. Each aircraft
is then to fly over the radar, again noting the time (or DME and
VOR readings for the cloud survey aircraft). The aircraft may
then land.
By 1030 on the morning of the next operational day following the
flight, hard copy navigation outputs from the data recording systems
will be required at approximately 6-second resolution for all times
within 0.5 min of passing over the VOR or landmark. The apparent
coordinates of these positions will then be checked for accuracy.
Survey aircraft crews will provide hard copies of their written or
voice tape notes by the same time.
All aircraft data systems will record the air temperature and dew­point
(if available) during the landing while the aircraft is within
III-34
(
10 m of the runway, and. preferably. just before touchdown. The
indicated pressure altitude just after touchdown is also to be
recorded. After the aircraft lands. one of the crew m'embers is to
make a special reading of the FAA instruments to determine the sur­face
air temperature, dewpoint, winds, and altimeter setting. Such
a special reading is to be made within 5 minutes of landing and will
be used to help verify the calibration of those aircraft instruments.
These and other instruments will also be calibrated according to the
normal procedures for those instruments. by tower fly-bys when possi­ble,
by formation flights with other ai~ra:ft, and by ascents in air
being measured'by a rawinsonde. Instruments will be assumed to be
uncalibrated Wltil thus proven. Some calibration experiments that
will be requested at Miles City are listed in appendix E.
III-35
C. Radar Utilization
Mites City Radar
The SWR-75 radar located near the Miles City Airport will be manned
from 1130 through at least 0040 6 days each week. If echoes are
present at 0040. operation will continue until 0200. Anytime pre­cipitation
echoes exist within 150 km of the radar, they will be
recorded on magnetic tape for detailed computer processing by the
Bureau of Reclamation CYBER-74 computer facility in Denver.
Two radar operators, an electronics technician, the mission coor­dinator
and the aircraft controller constitute the onsite personnel
responsible for maintaining and operating the radar system.
The electronics technician shall perform a complete electronic
calibration of the radar system on the morning of each operational
day (6 per week). This calibration shall strictly adhere to the
procedures described in appendix D. The technician shall daily
perform preventative maintenance and any needed maintenance tasks
and attempt to have the system ready for operation by 1130. If
any malfunctions will cause a delay in availability of the radar.
the project director shall be notified immediately and briefed on
the nature of the malfunction and the anticipated time that the
system will become available. All calibration data must be logged
on the appropriate forms. One copy of the calibration data will
be in the radar and another copy will be sent to Denver at the
time the tapes are mailed. The calibration procedures are listed
in appendix D. Also described in appendix 0 are procedures for
sphere calibration of the radar system. This calibration shall be
accomplished during the months of April and June and again during
the first half of August.
Before initiation of any data recording. the radar operator shall
complete the checklist of appropriate switch settings which con­trol
the manner in which data are recorded and displayed. These
are the 2!!.!l. switch settings, and hence only mode. to be used for
recording radar data. If for any reason the radar data is recorded
in anything but the normal JDOde. this information should be logged
on a form which lists the following information.
1. TAPE LD.
2. Begin time and record count
111-39
3. End time and record count
4. Reason for deviating from standard data collection mode
5. Switch settings changed and their values
The above information should be given for each appropriate block
of data so recorded. One form should be filled out for each tape
containing nonstandard data. This form should be firmly attached
to the corresponding tape prior to shipment to Denver. A copy of
the checklist is included in appendix B. One is referred to appen­dix
A for a discussion of the full range of capabi li ties of the
radar.
After the checklist has been completed, the transmitter shall be
turned on and the radar will be used for surveillance to a range
of 250 km. While in the surveillance mode, one volume scan to 130
will be taken twice per hour, on the houT and 30 minutes past the
hour. This scan wi 11 be recorded and wi 11 be noted in the Radar
Log Book. Its purpose will be to detect any echoes within 150 km.
Once echoes exist within ISO km. recording of 130 volume scans
(requiring 5 minutes) will begin iDUllediate1y at exactly the appro­priate
2, 7, 12. 17 ..... 52, and 57 minutes past the hour. This
11-1-40
"matches" the 1· scan with the rain gage data. The radar digital
clock is to be set by WWV before recording cOllll1ences.
By 1145. the forecaster will be briefed concerning the location.
size. shape and maximum intensify of any echoes that exist. If
no echoes exist, the radar shall continue to be operated in the
surveillance mode until 1230. At this time the mission coordinator .~ I
will brief the radar operator concerning the forecast and provide
any special instructions for further radar operations. Notes con-cerning
the briefing to the forecaster and from the mission coor­dinator
will be placed in the Radar Log Book.
If a research flight is planned, the mission coordinator and the
aircraft controller will report to the radar at least 15 minutes
prior to the intended takeoff of the first aircraft. Both the
tliF and VHF radios in the radar and aircraft will be "ground
checked" prior to takeoff. The aircraft controller will determine
the assigned IFF transponder code for each aircraft and set that
code into one of the three sets of thUJllbwheel switches for record­ing
the aircraft location.
I f recording of echo data has not been in progress prior to the
takeoff of aircraft, the sequence of 5-minute, 13· volUJl1e scans
III-41
will begin at this time and continue throughout the duration of
the flight even if no echoes occur. Thus, a radar tape will exist
for the duration of every research mission, even if echoes do not
develop. If echoes continue to occur after the flight, recording
will continue until either no echoes are present within ISO km or
at the scheduled shutdown time.
Two tape recorders are furnished with the radar. Al though the sys­tem
is designed to switch automatically to the other recorder when
one tape is full, the data processing procedures require complete
scans on a given tape. Therefore. it is necessary to change record­ers
manually when one tape nears its record capacity. The record
count should be monitored, and when 12,500 records have been
recorded (one tape will hold slightly more than 13,000 records).
the switch to the other recorder should be made at the completion
of the volume scan in progress. The best way to note the end of
a volume scan is to observe the elevation angle being displayed.
It will increment upward by 1° from 1.0 through 13.0 and remain
at each degree for about 20 seconds during the volume scan. At
completion, the elevation angle will decrease rapidly to about
0.7° as set on the elevation angle handwheel. When this occurs,
at least two end-of-file (EOF) marks should be placed on the full
tape by depressing the EOF switch on the digital control panel, the
111-42
record count should be reset to zero and the tape recorder not in
use should be selected by depressing the appropriate switch on the
Digital Control Panel. Each tape will be labeled ",ith the Julian
date, sequence code, start and stop time and beginning and ending
record count. The exact procedures are described in appendix C.
Proper entries shall also be made into the Radar Log Book to doc­ument
all tape changes. The only exception to the above discussion
",ill be in the event of a power failure or purposely turning off
the main power to the system. Anytilte the main pever to the system
is interrupted, the tape being used for recording is to be removed
and properly identified and a ne", tape is to be used for further
recording.
All tapes recorded for a given day shall be left in the workshop
area in Betal tape mailing box"es. The technician ",ill deliver all
tapes recorded the previous day and a copy of the calibration data
to the project secretary after the calibra'tion has been completed.
The secretary will make a log of all tapes and the date they were
mailed to Denver. The secretary will be responsible for promptly
mailing the tapes with the appropriate calibration data included
in the same container.
During a research mission, the aircraft controller will monitor
the project VHF frequency (118.55 or 122.9) and the VH~ frequency
III-43 ~
assigned the aircraft for contacting Salt Lake City ARTCC. All
cOllllllUnications between the aircraft controller and the pilots of
the aircraft will be on the project frequency. The pilots will
also use this frequency when it is necessary to coordinate the
location of one airplane with respect to another. The mission
coordinator will communicate with the aircraft scientists or
observers in the aircraft on the lIHF radio. The mission coordi­nator
and aircraft controller, and the aircraft scientist and
pilot, will utilize voice communications to complete the link in
all necessary coordination of the acti vi ties.
Ultimate responsibility for maintaining safe separation distances
will rest with the pilots during nonstandard formation flights
operating under provisions of required regulations while performing
their mission in conformance w'ith. an ATC clearance. The Salt Lake
City ARTCC will issue all clearances and must approve any devi­ations
requested.. The aircraft controller in the SWR-75 radar will
provide navigation assistance only to the extent of aircraft loca­tions
relative to cloud echoes and information concerning maximum
reflectivity values and the horizontal extent of cloud echoes. At
no time will the aircraft controller attempt to exercise "terminal
control" guidance of the aircraft.
The radar operator will be responsible for entering operator note­book
entries to the data tape during intensive case study flights.
III-44
The mission coordinator will supervise the radar operator to assure
pertinent data entries are made. The coded entries and a brief
explanation of their meaning is presented in figure 4. The exact
manner in which they will be routinely used will evolve as experi­ence
with the system is gained.
Bakel" Radal"
A C-band digitized radar will be operated at Baker, Mont., approx­imately
125 km east of Miles City (see fig. 1). This radar will
be operated by Universi ty of North Dakota personnel and will be
primarily concerned with possible downwind effects attributable to
HIPLEX. It will be utilized primarily for data collection, which
will be processed by the University of North Dakota computing facil­ity
with l:i.ttle emphasis on real-time interpretation of data.
One electronics technician and two radar/rawinsonde operators will
be the only personnel available. They will operate on the same
6~day week as the Miles City radar and aircraft crews. The antic­ipated
period of radar data collection will be from 1300 to 2340
each day, with one daily rawinsonde released at 0830. The routine
work schedule is given in table 3.
A complete electronics calibration is to be performed on the morning
of each operational day strict ly according to the procedures of
111-45
~ 2 3 • 5 6 7 8 9 rJ IsuSreveedyl ~'0' ~Entry [E;xJit ~Base ~Mid ~Top
10 11 12 13 " 15 16 17 18 EB E:J ~ ~ EJ ~ ~ E:J E:J Range
Button:
1-4 individual aircraft
5-6 cloud penetration data
7-9 seeding data
10 case muaber
11-12 start and stop times (penetrations, seeding, updrafts)
14 temperature at a given altitude. Thus temp. would always
be associated with an aircraft and altitude
15 azimuth and range to the center of the case
5 digits: 320 26
AZ Range
16 rain observed intensity: 0 '" none, 1 .. virga. 2 .. light
rain. 3 .. moderate rain, 4 '"
heavy rain
17 other: any other message which must be written into Radar
Log Book
Figure 4. - SWR-75 op_erators notebook
trI-4'>
appendix D. A copy of the calibration form should be sent to the
University of North Dakota with each shipment of data tapes. Pre­ventive
maintenance shall also be performed each morning, and other
maintenance as soon as practical after any system failure. Sphere
calibrations (see appendix D) shall be performed during April, June,
and the first half of August.
As discussed for the SWR-75 system, this radar will also be operated
in the surveillance mode with a volume scan each hour and half hour
until echoes exist, in this case within 170 km of the radar. When-ever
echoes are closer than 170 km, repeated volume scans will be
taken until all echoes completely dissipate, move beyond 170 km,
or 2340 hours occur.
Because the downwind radar does not have automatic control of eleya­tion
angle stepping of the antenna, the operator will have to man­ually
step the antenna elevation by 10 increments for recording a
volume scan. The radar does not discontinue recording while the
antenna is in transit from one elevation to another. Therefore,
the operator will have to choose a portion of the area in which
to make the elevation steps. Ideally, the area should be echo
free, but if this is not possible the antenna should not be stepped
while it is oriented over the rain gages.
11[-47
Because volume scans require continual manual operation, one will
not be recorded every 5 minutes. Instead, a 16° volume scan will
start at IO-ainute intervals beginning at 2 lIinutes after the hour,
as determined froJQ WHY; a 1° "A scan" will be recorded at IO-minute
intervals, beginning at 7 Ilinutes after the hour. The 16° scan
will start with the LOo "A scan," followed by 1.5° steps to 2.So,
4.0°,5.5°, etc., up to 16.0°. Since the downwind radar has only
one tape recorder. the tape changes should be scheduled to coin-cide
with completion of the 1.0° "A scan." Volume and "A scans"
should always be started exactly 2, 7, 12, 17, etc., minutes after
the hour as determined from WWV. As with the SWR-75 radar, only
the switch settings noted in appendix A are to be used during !!!l.
data recording.
The downwind radar has an addi'tional PPI that has independent range
selection from the master console PPI. The additional or remote
PPI has a super-8 movie camera J:lo.1Jnted to take time-lapse photo-graphs
of the cloud video, date, time and ant.enna eleva.tion angle.
The system was designed such that a frame was expo,sed at I-minute
intervals. It sho,uld be modified sucb that the antenna position
will control the exposure rate .~o each exposure corresponds to a
360° azimuth sweep. The camera should be operated wheneyer radar
data are tape recorded.
111-43
The radar wi 11 be equipped wi th a VHF radio. It can be monitored
to obtain limited inforll3tion on the location of aircraft during
extensive case study missions. There is also an L-band IFF system
which will display aircraft locations. It does not have the capa­bility
to distinguish unique transponder codes and does not record
the aircraft location on tape. The system should provide some
information such that notes concerning the location of test cases
between the two radars can be recorded. Since there will not be
a license to allow the radar to transmit on the project VHF fre­quency.
and the receiving range will be limited. the extent to
which the downwind radar will remain aware of aircraft operations
is an unknown.
D. Rawinsonde Observations
Two WSSI rawinsonde crews will be available at the Miles City site
to obtain rawinsonde data for direct program support. These crews
wi II be available to prOVide rawinsonde and weather forecast sup­port
services during the period 0800 to 2130 on all operational days.
A minimum of one routine sounding per day will be taken on a 6-day­per-
week basis. A routine release will be made at 0830 MDT (1430 Z).
This first rawin will be primarily used in developing the 1200 fore­cast
and for modeling purposes.
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Additionally. serial soundings will be taken on operational days
and. as decided by the project director. days when convective activ­ity
is forecast to occur. The main objective will be to obtain a
sounding inunediately prior to the onset of general convection, and
to continue releases on a routine basis throughout the entire con­vective
cloud development. and dissipat.ion period, or until the onset
of darkness. whichever occurs first. The launch time of t.he initial
serial sounding will be flexible, depending upon the 'forecast onset.
of convection or when cumulus begins. Aft.er the init.ial launch,
releases may cont.inue routinely at between 2- and 3-hour intervals,
at the project director's discretion.
In addition. an 0830 rawinsonde release will be made 6 days per week
from the downwind radar site at t.he Baker, Mont., airport per instruc­tions
from the project director at Miles City. A Weather Measure
Corporation RD-65 rawinsonde system incorporated in the radar van
will be used for data collection. It is anticipated that a hangar
space will be utilized for balloon inflation and supply storage.
This site will also be equipped with a t.ime-share computer terminal
for rawinsonde processing.
Rawinsonde receiving and recording equipment will be calibration
checked and adjusted (if necessary) to manufacturer specifications
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prior to each release. At least weekly checks of the receiver antenna
orientation and level will be performed by contractor personnel and
noted in a log. These checks and all phases of the data collection
and reduction will be monitored throughout the field season on a
spot-check basis by DAWRM personnel.
All sOWldings ""ill be made in accordance with specifications contained
in the latest revision of Federal ~feteorological Handbook NO.3,
Radiosonde Observations. It will be attempted to track and record
all sondes to the IOO-mbar level if practical. In the event that a
sonde cannot be tracked and recorded to at least the 400-mbar level.
an additional sounding will be required, again attempting to reach
the IOO-mbar level.
Data collected from the routine morning sounding wi 11 be processed
inunediately and utilized for forecast purposes. All other soundings
will be processed in as near "real time" as practical. However.
obtaining serial release data will take precedence over data reduc­tion.
All soundings will be processed using facilities of the CYBER-74
time-share computer system. Time~share terminals will be located in
the Miles City rawinsonde trailer and Baker radar van for this pur­pose.
Both should call 232-5717 for computer access.
III-51
E.. Surface Measurements
PNeipitation
Approximately 160 recording rain gages of varying sophistication
will be utilized during the summer field season. The installation,
operation, and data handling associated with these gages will
require a team of professional meteorologists, technicians, and
data clerks. The total effort will require close coordination to
accODlplish the objectives of the precipitation measurement por­tion
of HIPLEX.
The Montana Department of Natural Resources and Conservation (DNRC)
will establish all rain gage sites in the primary network and
clusters. They will choose locations, arrange leases and permits,
and fence all sites as necessary. The DNRC will abo calibrate,
install, and operate all Belfort weighing rain gages.
All Belfort gages will use 24-hr chart drive gears (one rotation
per day) so that seven traces will result on the chart between
weekly servicing. The funnel. will be removed from the bottom end
of each gage's collector tube allowing water to evaporate" from
the -catch bucket between rainfall periods. The resulting slight
separation between daily traces during nonrainy periods will
III-52
greatly facilitate chart reading. To insure that water is ade­quate
for evaporation, at least 25 ram (l in) should always be
left in the bucket after servicing, as determined by the absolute
chart reading. It may be necessary to increase this to as much
as 50 mm (2 in) during the hottest portion of the swmner.
All gages will be precalibrated using Belfort standard weights
prior to installation in the field. Calibrations must be accurate
to within plus or minus 0.25 nun (0.01 in) over the full ISO-nun
(6-in) span for the unit to be declared acceptable for field instal­lation.
After the calibration is achieved, the gage mechanism will
be secured before it is transported. The gage calibration will be
rechecked and adjusted, if necessary, to provide the same accuracy
after it is installed at its field station. Subsequent recalibra­tions
will be performed at approximately the midpoint and at the
end of the data collection season.
All spring-wound and electrically driven gage clocks will be test
run for at least 2 weeks prior to field installation. This will
be accomplished at the Miles City headquarters. Necessary adjust­ments
will be made so that each unit perfoTDlS to an accuracy of
at least plus or minus S min per week prior to field installation.
Minor adjustments will be made when necessary during routine field
III-53
servicing to maintain this accuracy throughout the data collection
Each Belfort gage will be visited once per week for routine serv­icing.
During servicing the gage chart will be changed. The date~
time~ location~ instrument identification. water amount, and serv-icing
personnel's initials will be marked on the chart at both
time of installation and removal. A log form specifying pertinent
service information will be completed after each gage servicing.
Minor failures of manual gages will be repaired during routine
servicing. A field recheck of the repaired gage will, generally.
be made within 2 days after repair. Any gages which experience
major failures (for example~ vandalisJl), will be removed from the
field and re"turned "to the Miles City headquarters for repair.
Strip chart data obtained from the Belfort gages will be reduced
at the Miles City headquarters. They will be compiled into the
computer-compatible form to be specified by DA.WRM in Denver.
Manual network data reduction will commence upon receipt of indi­vidual
charts and continue throu~hout. and for some time- after. the
field season. Each chart will be spot checked by the data clerk
supervisor within 3 days of the chart change. A.ny problems will
immediately be reported to the DNRC supervisor. All charts will be
reduced at IS-minute intervals (starting on the hour) by noting
the chart reading to the nearest 0.2S mm (0.01 in). Unless a suit­able
chart reduction machine is available, this is most efficiently
done by two persons. One reads the absolute inches of water from
the chart trace while the other writes the information on an IBM
card punch form. A second independent reading should be made at
a later date. Both sets of readings are entered into the CYBER-74
computer system for comparison, and all discrepancies greater than
0.25 DIll (0.01 in) are then resolved by reference to the original
charts. These procedures are further discussed in Montana Technical
Report 76-1.
The installation, maintenance, and operation of the entire LANDSAT
and memory gage systems will be the responsibility of Western
Scientific Services, Inc. (WSSI). It is not practical to determine
what routine servicing schedule will be required for the LANDSAT
and memory gages until additional field experience is gained. Thus.
the details regarding maintenance needs will evolve during the field
season. However, whenever a LANDSAT or memory gage is discovered
to be malfunctioning, WSSI personnel will promptly repair the gage.
Data from the LANDSAT gages will be recorded on cassette tape at
the central station in the center of the LANDSAT portion of the
In-55
primary network. Data from the memory gages will also be recorded
on cassette tape on a receiving and recording systell carried aloft
by a light aircraft. Flights will be required on approximately an
every other day basis to prevent data loss because the memory capac­ity
of the gages is 256 IS-minute intervals.
All collected data will be promptly entered into the CYBER-74 com­puter
system for initial error analysis.
The amount of water in each wedge-type gage (to the nearest 0.25 llIII
(0.01 in) will be logged at each visit to any rain gage site. The
date, time, and observer will also be noted. The gage will then be
completely emptied by sharp downward shakes of the wrist. There­after,
a premeasured amount of light oil will be added. This will
reduce evaporation. Finally the gage will be returned to its holder.
Hail pads will be located at all Selfort and LANDSAT gage sites.
These will be inspected during each routine service visit. Those
units showing any indications of hail damage will be replaced with
a new pad, and the entire pad with damage (foil and styrofoam) will
be transported to the Miles C.ity headquarters. Care should be
taken to prevent further damage and denting to the pads during
transport.
III-56
Hail pads will consist of 25-mm (I-in) thick styrofoam square
blocks, 30S nun (12 in) on a side, which will be furnished by DAWRM.
The project director will be responsible for covering the styro­foam
with I-mil alUllinum foil (also furnished by DAWRM). which is
to be wrapped over the top and sides of the styrofoam blocks, and
stapled around the bottom of the block. The aluminum is to fit
over the styrofoam as snugly as practical. The completed hail pads
are to be placed on the ground after the ground surface has been
cleared of all grass and litter and leveled to a hard surface.
The pad is to be secured firmly to the ground by a large (about
ISO-nun-long) spike or nail driven through the middle of the pad.
No brush or other obstructions (including rain gages) should be
closer to the pad than twice the height of the obstruction. Grass
within 1 meter of the pad should be kept trimmed to below about
100~nun height. Also, the ground under each pad should be checked
periodically, and cleared of any growth, to prevent a "spongy"
surface under the pad.
Hail pads must be marked in the field with their location and "on"
date and time (at the time of initial exposure), and "off" date
and time (at the time of replacement). The observer's initials
should also be noted at both on and off times. These notes are to
be permanently placed on the bottom (non-fail-covered) side of the
pads with felt-tipped pen (dark blue or red color) which uses
waterproof ink.
III-57
To operate the precipitation gage networks during 1976 in a reason-able
and syst'ematic way, a task schedule is mandatory. as the inter-play
of manpower to operate all gages is significant. A detailed
task completion schedule follows:
January 30, 1976
February 13, 1976
February 16, 1976
March 5, 1976
March 19, 1976
March 22. 1976
March 29, 1976
Additional fencing materials are ordered.
Siting of 72 new rain gage plots begins.
Bench calibration of 41 Belfort rain gages
already at Miles City begins.
Transport of 50 Belfort rain gages from
Denver. Colorado. to the Miles City
headquarters.
Completion of new gage site selection.
Permission for their use is secured from
private landowners and is requested from
public agencies. Bench calibration of all
Belfort rain gages is completed.
All fencing materials are delivered. Fenc-ing
of new gage sites begins. Installation
of Belfort and ~edge-type rain gages begins.
West,~rn Scientific personnel arrive with
50 LANDSAT rain gages and 20 memory rain
gages. Installation of the LANDSAT rain
gages begins.
III-58
April 5, 1976
April 15, 1976
June 14. 1976
June 25, 1976
August 2, 1976
August 13, 1976
October IS. 1976
Field calibration of Belfort rain gages
in the field begins. Installation of the
memory rain gages hegins.
Fencing is completed. All rainfall net­works
aTe calibrated and fully operational.
Reduction of rainfall data begins.
Field recalibration of Belfort rain gages
begins.
Field recalibration of Belfort rain gages
is completed.
Field calibration check of all rain gages
begins. Removal of all rain gages begins.
Removal of all rain gages is completed.
Computer data reduction of all 1976 rain­fall
data is completed.
Cz,qwj Condensation and Ice Hue Z,8i
Cloud condensation nuclei Deasurements will be made once each oper-ational
day at 1500. I'iSSI radiosonde personnel will be trained
by J. McPartland in the operation of the Allee thermal diffusion
chamber to be utilized. A series of photographs will be taken
each day. The first will display an identification card showing
the location, date, and tille observations were started. The
III-59
relllaining pictures wi 11 record CCN concentrations at supersatura­tions
of 0.5, 0.8, and 1.1 percent. Three individual samples will
be obtained for each supersaturation. The droplet concentration
for each of the individual samples will be recorded on a sequence
of four pictures. The first exposure will be made at the instant
that droplets are first observed forming in the chamber. The
remaining frames will be taken at I-second intervals. This process
will allow maJ(imum concentrations to be determined in the data
reduction process. All exposed film wi 11 be conveyed to
J. McPartland at Miles City headquarters.
Ice nucleus measurements will be obtained using 0.45_pm membrane
filters contained in factory-loaded plastic field monitors. One
membrane will be exposed each operating day of the field season.
This sample will consist of air samples drawn through the membrane
for I minute out of each 5 minutes during the period 1200 to 2100.
These start and stop times will allow routine servicing to be
accomplished by WSSI radiosonde personnel while still yielding
a good sample of the typical daytime period of convective activi ty.
Equipment to be utilized will consist of two timers. a small vacuum
pump. and a flowmeter. The first timer will be used to establish
the daily operating period of 1200 to 2100. This unit will be
checked each operating day and if necessary. time corrected for
power outages. The second timer wi 11 be set to operate dte vacuum
pump for 1 mnute of each 5-minute time block during the daily
III-60
period. Complete operating instructions will be furnished with
the unit. Personnel servicing the equipment ....ill monitor its
function once each day and, if necessary, adjust the controllable
flowmeter to achieve a sample flow rate of 2.0 1m. A log of equip­ment
operation and servicing will be maintained. Exposed membranes
will be sealed, labeled with their place of origin and date of
exposure, and forwarded to Or. G. Langer at NCAR for processing by
his lab.
Time-lapse Super-8-1llDl films from the stereo pair of ground-based
cameras will be changed every fourth day, preferable during night
hOUTS or early morning. The month card will be changed when appro­priate
and the date corrected on the digital clock at the end of
April and June. The clocks will be checked for evidence of power
failures and reset if necessary. The I-minute timers are to
trigger the cameras on the minute as given by the WWV time signal.
Digital clocks are to be a half minute fast so that they will not
be changing their numbers during a photo.
The l6-mm time-lapse camera will be set in place at the rawinsonde
site during preparations for aircraft examinations of the clouds.
The crew at the site will be advised by phone from the radar of
the azimuth of the case study and will rotate the camera to that
1I1-61
azimuth. The azimuth of the cameTa should not be changed unless
a majoT correction is necessary. The timer and clock will be set
as above and a date card lIust be placed in view. The camera main­spring
must be fully wound before operation; it will then be good
for 10 hours. Film will be changed when necessary; many days of
operations can be recorded on one film.
Still photographs of clouds will be made at irregular intervals.
The frame number, time, date, location, and subject will be
recorded manually for each photo. At the end of the day (or begin­ning
of the next) the last photo should be of a display giving
the date and times of all photos taken that day.
F. Satellite Data Collection and Analysis
Satellite iIlagery will be received continuously 24 hours per day for
sectors appropriate to HIPLEX operational priori ties. The standard
observation sector will be the KB-4 i-mile sector. This will pro­vide
infrared imagery at night and visible imagery during the day
covering the entire High Plains. Special half-mile sector coverage
may be obtained from the SA-2 se~tor during intensive Miles City oper·
ations as required by the field site director. Each change of sector
coverage requires two telephone calls to the SFSS in Kansas City
(8.758-3749): (1) a call requesting the change from the standard
sector to the special sector; and (2) a call requesting the change
111-62
back to the standard sector. upon completion of special sector cov-erage.
These calls must be placed upon completion of transmission of
the current sector and before transmission of the special sector
begins. ooE5-1 illagery begins transmission at 12 and 42 minutes
after the hour, and SMS-2 imagery begins transmission at 27 and
57 minutes after the hour. Transmissions last 11 to 15 minutes.
Thus. when switching coverage between satellites, care must be taken
to receive the start signal so that data are not lost.
Routine analysis of satellite imagery for field operations should
include the following:
Analysis of location, rate of development, and movement for
all major convective cloud systems within sao kIl. of the field
site.
b. Notation of all meso/synoptic-scale organizations within
1.000 kilt of the field site. including downwind systeIlS.
c. Special notation of mesoscale triggering mechanisms including:
(I) Mesohigh arc lines
(2) Gravity waves
(3) Convergence lines
III-63
I .'~
I,~ . ~
(4) Areas of differential heating - fog/status. etc.
(5) Jet-lets
(6) Vorticity sheets
This information should be reported on standard forms shown in
appendix J.
In addition to the detailed satellite imagery observation log. a daily
summary log describing the important features of each day shall be
maintained. This will provide a quick look tabulation of important
meteorological features visible on the imagery. the sectors received.
and image quality, as shown on the Imagery Data Log (see appendix J).
Laserfax iJnagery should be mailed to DAWRM. Attn: Dave Matthews. at
the end of each week for further analysis. The attached form should
be used to log all important phenomena routinely as t.hey evolve.
Imagery should be archived chronologically with satellite logs for
ea~h day maintained in each day's file.
Digital Data Collection from White sands Missil-e Range (WSMR)
The project meteorologist. as required, will inform CSU personnel
at White Sands. telephone (8·898-1488 or 1489) of the scope of each
days' operation following the morning briefing. if applicable. When
special extended observations are required he shall so infot"lll these
111-64
personnel prior to 1100 MDT. If this inforlll8.tion is not provided,
digital satellite data will be collected for climatological and
case study analysis from 1600 GMf (1000 MDT) to 0000 GMT (1800 MDT).
G. Safety Considerations
Aircr>aft Operations
The regulations below are general in nature and it is expected that
each aircraft group associated with the HIPLEX program may wish to
adopt more stringent regulations. It will be the responsibility of
each aircraft command pilot to inform all personnel participating
in any way with the aircraft operations of additional safety rules.
(1) Ground Safety. - All ground operations, including instal­lation.
testing and maintenance of scientific equipment, aircraft
maintenance. loading. fueling, and aircraft movements will be
conducted by or under the direct supervision of appropriate
personnel supplied by the contractor.
No sm